it has been discovered that the addition of a relatively small amount of zeolite a to a regular or standard feed for laying chickens or hens effectively improves the quality of the egg shell with no significant changes in egg production , egg weight or feed consumption . zeolite a is preferably added in amounts of from about 0 . 25 percent to about 4 . 00 percent of weight of the total feed . a typical feed preparation for large scale laying hen operations comprises the following by weight percent : ______________________________________corn 62 - 68soy bean meal 18 - 24limestone 5 - 9alfalfa meal 1phosphates 2sand 1 - 2vitamins , amino acidssalt and other minerals 0 - 1______________________________________ zeolite a is added to such feed formulation in small amounts by weight percent of up to about four . greater amounts may be used , but may deprive the layers of the desired amount of nutrients . greater amounts are also likely to be cost ineffective . a preferred amount of zeolite a is from about one - half to about two percent by weight of the total feed formulation . a most preferred amount of zeolite a is about 0 . 75 to about 1 . 50 weight percent of the total feed formulation . the most convenient means of measuring egg shell strength is by measuring the specific gravity of the egg . this is simply done by immersing the egg in solutions of salt water of varying strengths . it is well known in the art that specific gravity correlates with egg shell strength . as specific gravity of the egg is raised , the strength of the egg shell is increased . using ethyl eza ® zeolite , a commercially available sodium zeolite a , a number of tests were conducted to determine the effect of zeolite on egg shell quality . procedure : 480 hens ( dekalb xl pellets ) were divided into eight equal groups and fed one of the following dietary treatments for a minimum of six weeks : ______________________________________ calcium zeolite adiet ( wt . %) ( wt . %) ______________________________________1 4 . 00 02 4 . 00 0 . 753 4 . 00 1 . 504 4 . 00 0 . 68 * 5 2 . 75 06 2 . 75 0 . 757 2 . 75 1 . 508 2 . 75 0 . 75 ** ______________________________________ * diet not adjusted for calcium ** zeolite added on top except diet not adjusted for cl the diet fed to the hens consisted principally of corn supplemented with a soybean meal ( sbm ) and limestone . smaller amounts of alfalfa meal , dicalcium phosphate ( digalp ), a synthetic amino acid ( dl - methionine ), salt , a commercial vitamin and mineral supplement for layers ( micro - mix ). sand and / or hydrochloric acid ( hcl ) were added to some diets . each diet assured that the hens received all of the required nutrients and minerals . diets 1 - 4 contained 1 , 238 calories per pound , 16 % protein , 0 . 55 % total sulfur amino acids , 4 % calcium and 0 . 70 % total phosphorous . diets 5 - 8 contained 1 , 292 calories per pound , 16 % protein , 0 . 55 % total sulfur amino acids , 2 . 75 % calcium and 0 . 70 % phosphorous . all diets were isocaloric and isonitrogenous within treatments and are detailed in table a . table a__________________________________________________________________________ diet no . experimental diets for zeolite study ( weight percent ) 1 2 3 4 5 6 7 8ingredient 0 . 0 0 . 75 1 . 50 . 68 ( special ) 0 . 0 0 . 75 1 . 50 0 . 75__________________________________________________________________________ 4 . 00 % calcium 2 . 75 % calciumcorn 63 . 80 63 . 80 63 . 80 63 . 80 67 . 83 67 . 83 67 . 83 67 . 83sbm 21 . 41 21 . 41 21 . 41 21 . 41 20 . 69 20 . 69 20 . 69 20 . 69alfalfa meal 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00dicalcium phosphate 2 . 07 2 . 07 2 . 07 2 . 07 2 . 03 2 . 03 2 . 03 2 . 03limestone 9 . 14 9 . 14 9 . 14 9 . 14 5 . 87 5 . 87 5 . 87 5 . 87dl - methionine 0 . 01 0 . 01 0 . 01 0 . 01 -- -- -- -- salt 0 . 35 0 . 10 -- 0 . 35 0 . 35 0 . 10 -- 0 . 10micro - mix 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50sand 1 . 72 0 . 82 -- 1 . 04 1 . 72 0 . 82 -- 1 . 23zoelite a -- 0 . 75 ** 1 . 50 ** 0 . 68 * -- 0 . 75 ** 1 . 50 ** 0 . 75 ** hcl -- 0 . 40 0 . 57 0 . 00 -- 0 . 40 0 . 57 -- 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0__________________________________________________________________________ * 0 . 68 is the special zeolite . ( diet 4 ) ** 0 . 75 and 1 . 50 is zeolite a . all eggs laid during a 3 - day period each week of the experiment and the first week prior to the experiment were used for specific gravity and egg weight measurements . the results are summarized in tables b , c , d , e , f and g as follows : table b__________________________________________________________________________egg specific gravity * no . of avg . fordiet eggs week 0 week 1 week 2 week 3 week 4 week 5 week 6 week 7 week 8 8 weeks__________________________________________________________________________1 - 4 240 80 . 24 80 . 33 80 . 70 81 . 03 80 . 90 80 . 52 78 . 21 80 . 76 80 . 69 80 . 395 - 8 240 80 . 04 78 . 69 78 . 32 79 . 15 78 . 57 77 . 75 76 . 48 78 . 99 78 . 80 78 . 341 and 5 120 79 . 88 78 . 37 77 . 63 78 . 16 77 . 96 77 . 14 75 . 42 77 . 90 77 . 74 77 . 542 and 6 120 79 . 64 79 . 13 79 . 47 79 . 93 79 . 83 79 . 43 77 . 20 80 . 10 79 . 51 79 . 333 and 7 120 80 . 56 80 . 60 81 . 14 81 . 59 80 . 84 79 . 87 78 . 85 80 . 67 81 . 15 80 . 594 and 8 120 80 . 47 79 . 93 79 . 79 80 . 67 80 . 33 80 . 08 77 . 91 80 . 83 80 . 58 80 . 011 60 80 . 27 80 . 12 79 . 42 80 . 30 79 . 86 79 . 49 77 . 59 79 . 53 79 . 19 79 . 442 60 79 . 70 79 . 03 80 . 53 81 . 17 81 . 27 80 . 67 78 . 86 81 . 01 81 . 29 80 . 483 60 80 . 35 81 . 84 81 . 96 81 . 92 81 . 66 81 . 53 79 . 16 81 . 33 81 . 91 81 . 444 60 80 . 64 80 . 33 80 . 88 80 . 73 80 . 82 80 . 38 77 . 22 81 . 18 80 . 38 80 . 245 60 79 . 50 76 . 63 75 . 83 76 . 03 76 . 06 74 . 80 73 . 25 76 . 28 76 . 30 75 . 656 60 79 . 60 79 . 24 78 . 41 78 . 70 78 . 39 78 . 20 75 . 55 79 . 19 77 . 73 78 . 177 60 80 . 77 79 . 35 80 . 32 81 . 26 80 . 01 78 . 21 78 . 54 80 . 01 80 . 40 79 . 768 60 80 . 31 79 . 54 78 . 70 80 . 61 79 . 83 79 . 79 78 . 60 80 . 47 80 . 77 79 . 79__________________________________________________________________________ * divide by 1000 and add 1 to convert to actual specific gravity . table c__________________________________________________________________________egg production ( percent hen per day ) no . of percent avg . fordiet calculations week 0 week 1 week 2 week 3 week 4 week 5 week 6 week 7 week 8__________________________________________________________________________ weeks1 - 4 240 89 . 88 86 . 44 88 . 59 85 . 10 87 . 97 87 . 87 87 . 54 86 . 53 84 . 46 86 . 815 - 8 240 90 . 21 86 . 59 84 . 17 81 . 99 84 . 65 83 . 45 82 . 84 82 . 58 81 . 82 83 . 511 and 5 120 90 . 42 89 . 25 88 . 50 85 . 82 87 . 86 87 . 74 85 . 48 84 . 82 85 . 25 86 . 842 and 6 120 90 . 08 84 . 55 86 . 43 84 . 96 87 . 13 86 . 46 86 . 69 84 . 67 82 . 71 85 . 453 and 7 120 89 . 58 85 . 12 85 . 46 81 . 98 86 . 32 83 . 93 85 . 02 85 . 65 84 . 22 84 . 714 and 8 120 90 . 08 87 . 14 85 . 12 81 . 42 83 . 93 84 . 52 83 . 57 83 . 09 80 . 36 83 . 651 60 90 . 00 90 . 00 90 . 07 86 . 19 90 . 00 88 . 33 86 . 67 84 . 76 87 . 38 87 . 932 60 90 . 00 83 . 62 85 . 95 85 . 39 87 . 84 88 . 86 89 . 10 88 . 15 82 . 09 86 . 383 60 89 . 67 84 . 76 88 . 81 84 . 52 86 . 90 87 . 38 86 . 77 88 . 46 85 . 27 86 . 614 60 89 . 83 87 . 38 89 . 52 84 . 28 87 . 14 86 . 90 87 . 62 84 . 76 83 . 10 86 . 345 60 90 . 83 88 . 49 86 . 91 85 . 45 85 . 71 87 . 14 84 . 29 84 . 87 83 . 12 85 . 756 60 90 . 17 85 . 48 86 . 91 84 . 52 86 . 43 84 . 04 84 . 29 81 . 19 83 . 33 84 . 527 60 89 . 50 85 . 48 82 . 12 79 . 44 85 . 74 80 . 48 83 . 28 82 . 83 83 . 17 82 . 828 60 90 . 33 86 . 91 80 . 72 78 . 57 80 . 72 82 . 14 79 . 52 81 . 43 77 . 62 80 . 95__________________________________________________________________________ table d______________________________________shell weight ( grams / egg ) no . of avg . fordiet eggs week 4 week 8 8 weeks______________________________________1 - 4 240 5 . 32 5 . 23 5 . 285 - 8 240 5 . 12 5 . 08 5 . 101 and 5 120 5 . 06 5 . 06 5 . 062 and 6 120 5 . 22 5 . 14 5 . 183 and 7 120 5 . 31 5 . 23 5 . 274 and 8 120 5 . 29 5 . 19 5 . 241 60 5 . 23 5 . 20 5 . 222 60 5 . 37 5 . 27 5 . 323 60 5 . 40 5 . 29 5 . 354 60 5 . 29 5 . 18 5 . 245 60 4 . 89 4 . 93 4 . 916 60 5 . 08 5 . 00 5 . 047 60 5 . 21 5 . 17 5 . 198 60 5 . 29 5 . 21 5 . 25______________________________________ table e__________________________________________________________________________feed consumption ( grams per hen per day ) no . of avg . fordiet weighings week 1 week 2 week 3 week 4 week 5 week 6 week 7 week 8 8 weeks__________________________________________________________________________1 - 4 240 105 . 48 108 . 16 109 . 76 110 . 13 112 . 85 105 . 64 110 . 57 115 . 53 109 . 765 - 8 240 103 . 91 101 . 62 106 . 01 96 . 66 107 . 96 103 . 42 107 . 12 112 . 09 104 . 851 and 5 120 112 . 06 105 . 92 109 . 32 107 . 44 112 . 54 106 . 08 110 . 57 116 . 80 110 . 092 and 6 120 101 . 85 104 . 96 107 . 04 105 . 92 109 . 13 102 . 66 108 . 82 113 . 69 106 . 763 and 7 120 102 . 08 105 . 07 107 . 99 101 . 47 110 . 17 105 . 25 109 . 16 112 . 40 106 . 704 and 8 120 102 . 78 103 . 60 107 . 20 98 . 76 109 . 76 104 . 12 106 . 84 112 . 35 105 . 671 60 113 . 25 109 . 55 112 . 98 115 . 07 117 . 42 106 . 76 113 . 94 119 . 90 113 . 612 60 99 . 45 106 . 05 107 . 28 110 . 78 111 . 20 102 . 75 109 . 22 113 . 21 107 . 493 60 104 . 65 109 . 60 111 . 13 108 . 85 111 . 98 107 . 66 110 . 73 115 . 78 110 . 054 60 104 . 56 107 . 43 107 . 65 105 . 82 110 . 78 105 . 38 108 . 40 113 . 21 107 . 905 60 110 . 86 102 . 30 105 . 65 99 . 81 107 . 65 105 . 41 107 . 21 113 . 69 106 . 576 60 104 . 24 103 . 88 106 . 80 101 . 05 107 . 07 102 . 57 108 . 42 114 . 16 106 . 027 60 99 . 52 100 . 53 104 . 85 94 . 08 108 . 37 102 . 83 107 . 59 109 . 03 103 . 358 60 101 . 01 99 . 77 106 . 75 91 . 70 108 . 74 102 . 87 105 . 28 111 . 48 103 . 45__________________________________________________________________________ table f______________________________________body welght ( grams per hen ) no . ofdiet weighings week 0 week 1______________________________________1 - 4 240 1 , 538 . 58 1 , 550 . 635 - 8 240 1 , 518 . 58 1 , 520 . 001 and 5 120 1 , 526 . 25 1 , 565 . 002 and 6 120 1 , 528 . 00 1 , 542 . 003 and 7 120 1 , 515 . 58 1 , 492 . 004 and 8 120 1 , 544 . 50 1 , 542 . 251 60 1 , 541 . 67 1 , 579 . 332 60 1 , 525 . 83 1 , 543 . 173 60 1 , 518 . 67 1 , 507 . 004 60 1 , 508 . 17 1 , 573 . 005 60 1 , 510 . 83 1 , 550 . 676 60 1 , 530 . 17 1 , 540 . 837 60 1 , 512 . 50 1 , 477 . 008 60 1 , 520 . 83 1 , 511 . 50______________________________________ table g__________________________________________________________________________egg weights ( grams per egg ) no . of avg . fordiet weighings week 0 week 1 week 2 week 3 week 4 week 5 week 6 week 7 week 8__________________________________________________________________________ weeks1 - 4 240 59 . 04 59 . 87 59 . 98 60 . 06 60 . 33 59 . 95 59 . 88 60 . 19 60 . 19 60 . 055 - 8 240 58 . 85 59 . 38 59 . 45 59 . 59 59 . 84 59 . 81 59 . 51 59 . 60 59 . 97 59 . 641 and 5 120 58 . 58 59 . 12 59 . 49 59 . 53 59 . 64 59 . 77 59 . 59 60 . 14 60 . 22 59 . 692 and 6 120 58 . 93 59 . 96 59 . 91 59 . 84 60 . 13 59 . 88 59 . 64 59 . 97 60 . 09 59 . 933 and 7 120 58 . 95 59 . 72 59 . 80 59 . 86 60 . 26 59 . 77 59 . 81 59 . 72 60 . 01 59 . 874 and 8 120 59 . 31 59 . 69 59 . 67 60 . 06 60 . 31 60 . 08 59 . 73 59 . 76 59 . 99 59 . 911 60 58 . 74 59 . 66 60 . 03 60 . 03 60 . 33 59 . 81 60 . 13 60 . 70 60 . 77 60 . 182 60 59 . 21 60 . 28 59 . 98 60 . 05 60 . 37 60 . 56 59 . 93 60 . 39 60 . 23 60 . 223 60 58 . 94 59 . 62 60 . 26 60 . 00 60 . 57 59 . 56 59 . 92 59 . 88 60 . 13 59 . 994 60 59 . 26 59 . 92 59 . 66 60 . 17 60 . 05 59 . 85 59 . 54 59 . 78 59 . 61 59 . 825 60 58 . 42 58 . 59 58 . 95 59 . 03 58 . 95 59 . 73 59 . 04 59 . 58 59 . 66 59 . 196 60 58 . 66 59 . 64 59 . 84 59 . 64 59 . 90 59 . 20 59 . 34 59 . 54 59 . 96 59 . 637 60 58 . 96 59 . 83 59 . 34 59 . 72 59 . 95 59 . 97 59 . 71 59 . 56 59 . 89 59 . 758 60 59 . 35 59 . 46 59 . 70 59 . 96 60 . 56 60 . 32 59 . 93 59 . 75 60 . 36 60 . 01__________________________________________________________________________ a review of the test data in table b shows that zeolite a provided a definite benefit on shell quality , and had no significant on the other qualities studied except possibly for shell weight . two concentrations ( 0 . 75 %, 1 . 5 %) were evaluate because of sodium limitations and for those levels , the data showed a linear relationship with concentration . in table c zeolite a had no significant effect on production (% hen day ). however there is some indication that a slight reduction occurred , particularly with diet 8 in the 2 . 75 % ca series ( i . e . low - ca ). in table d there appears to be an indication of some benefits from zeolite a . previous indications that feed consumption was reduced without any reduction in egg or body weight or in egg production could not be substantiated by the statistical data . as shown in table e 1 . 5 % zeolite a reduced feed consumption , relative to baseline , at both ca levels in weeks 1 and 4 . however this did not occur in the other six weeks of the trial . thus if we look at the results for the 8th week : ______________________________________ % ca run no . feed cons . ( g / hen / day ) ______________________________________2 . 75 1 113 . 692 . 75 2 114 . 162 . 75 3 109 . 032 . 75 4 111 . 48______________________________________ the reduced value is most likely attributable to a palatability consideration . laying hens usually eat more than they need . any factor , such as feed dustiness , can reduce intake by up to 5 % without an adverse effect . tables f and g show no significant benefits for body and egg weights . procedure : 480 hens were divided into eight equal groups and fed one of the following dietary treatments for a minimum of three months . ______________________________________ tsaa zeolite adiet ( wt . %) ( wt . %) ______________________________________9 0 . 51 010 0 . 51 0 . 7511 0 . 51 1 . 5012 0 . 51 0 . 68 * 13 0 . 61 014 0 . 61 0 . 7515 0 . 61 1 . 5016 0 . 61 0 . 68 * ______________________________________ * special zeolite 10 . 43 % ca and 0 . 52 % na . all diets were isocaloric and isonitrogenous and are detailed in table h . the components of the diets were also similar as those of example i . diet 9 - 12 contained 1237 calories per pound , 17 % protein , 0 . 61 % tsaa ( total sulphur amino acids ), 3 . 75 % calcium and 0 . 70 % phosphorus . diets 13 - 16 contained 1262 calories per pound , 14 . 78 % protein , 0 . 51 % tsaa , 3 . 75 % calcium and 0 . 70 % phosphorus . table h__________________________________________________________________________ diet no . experimental diets for zeolite study ( weight percent ) 9 10 11 12 13 14 15 16 0 . 51 % tsaa 0 . 61 % tsaaingredient name 0 . 00 % 0 . 75 % 1 . 50 % 0 . 68 ( special ) 0 . 00 % 0 . 75 % 1 . 50 % 0 . 68 ( special ) __________________________________________________________________________corn 67 . 65 67 . 65 67 . 65 67 . 65 62 . 07 62 . 07 62 . 07 62 . 07sbm ( 48 %) 18 . 19 18 . 19 18 . 19 18 . 19 23 . 81 23 . 81 23 . 81 23 . 81alfalfa ( 17 %) 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00 1 . 00dicalcium phos - phate ( 18 . 5 %) 2 . 12 2 . 12 2 . 12 2 . 12 2 . 01 2 . 01 2 . 01 2 . 01limestone 8 . 47 8 . 47 8 . 47 8 . 29 8 . 50 8 . 50 8 . 50 8 . 31dl - methionine -- -- -- -- 0 . 04 0 . 04 0 . 04 0 . 04salt 0 . 35 0 . 10 -- 0 . 35 0 . 35 0 . 10 -- 0 . 35micro - mix 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50 0 . 50sand 1 . 72 0 . 82 -- 1 . 22 1 . 72 0 . 82 -- 1 . 23zeolite -- 0 . 75 1 . 50 0 . 68 -- 0 . 75 1 . 50 0 . 68hcl -- 0 . 40 0 . 57 -- -- 0 . 40 0 . 57 -- total 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0__________________________________________________________________________ the results of the tests are summarized in tables p , j , k , l , m , and n . table p__________________________________________________________________________egg specific gravity * no . of avg . fordiet eggs week 0 week 1 week 2 week 3 week 4 week 6 week 7 week 8 8 weeks__________________________________________________________________________9 - 12 240 89 . 24 90 . 54 88 . 87 88 . 53 90 . 05 87 . 80 88 . 47 87 . 18 88 . 3413 - 16240 89 . 86 91 . 24 88 . 84 89 . 30 90 . 19 88 . 38 88 . 06 87 . 87 89 . 229 and 13120 89 . 34 89 . 93 87 . 90 87 . 94 88 . 88 86 . 81 87 . 67 86 . 66 88 . 1410 and 14120 89 . 38 90 . 35 89 . 01 88 . 60 89 . 93 88 . 25 88 . 43 87 . 03 88 . 9411 and 15120 90 . 44 92 . 07 90 . 13 90 . 01 91 . 29 89 . 40 88 . 88 88 . 57 90 . 1012 and 16120 89 . 06 90 . 71 88 . 40 89 . 11 90 . 40 87 . 89 88 . 06 87 . 84 88 . 939 60 89 . 27 89 . 25 87 . 83 87 . 46 88 . 36 86 . 14 88 . 09 86 . 49 87 . 8610 60 89 . 16 90 . 89 89 . 76 87 . 78 90 . 48 88 . 08 88 . 68 86 . 40 88 . 9011 60 90 . 04 91 . 73 89 . 92 90 . 00 91 . 23 89 . 27 89 . 07 88 . 07 88 . 9212 60 88 . 50 90 . 31 87 . 99 88 . 89 90 . 16 87 . 71 88 . 04 87 . 78 88 . 6713 60 89 . 41 90 . 61 87 . 97 88 . 43 89 . 39 87 . 48 87 . 24 86 . 83 88 . 4214 60 89 . 60 90 . 81 88 . 27 89 . 41 89 . 39 88 . 41 88 . 21 87 . 66 88 . 9715 60 90 . 83 92 . 41 90 . 33 90 . 02 91 . 35 89 . 53 88 . 69 89 . 07 90 . 2816 60 89 . 62 92 . 12 88 . 80 89 . 33 90 . 64 88 . 08 88 . 09 87 . 91 89 . 20__________________________________________________________________________ table j__________________________________________________________________________egg production ( percent hen per day ) no . of avg . percent forcalcula - week no . 12diet tions 1 2 3 4 5 6 8 8 9 10 11 12 weeks__________________________________________________________________________9 - 12 240 57 . 26 69 . 54 78 . 04 80 . 82 84 . 93 87 . 00 85 . 83 89 . 24 88 . 33 87 . 81 81 . 55 87 . 87 81 . 5213 - 16240 53 . 41 69 . 40 81 . 83 87 . 13 89 . 39 89 . 92 89 . 18 89 . 92 87 . 53 88 . 76 84 . 13 88 . 24 83 . 249 and 13120 53 . 73 71 . 31 82 . 12 85 . 19 87 . 94 87 . 86 86 . 34 89 . 48 89 . 22 87 . 63 82 . 06 85 . 29 82 . 3510 and 14120 60 . 23 71 . 31 75 . 71 76 . 47 82 . 74 89 . 22 89 . 52 91 . 19 88 . 69 90 . 12 86 . 19 90 . 60 82 . 5811 and 15120 51 . 93 64 . 32 78 . 01 85 . 01 87 . 65 89 . 17 85 . 76 88 . 61 86 . 73 88 . 86 83 . 31 87 . 59 81 . 4112 and 16120 55 . 43 70 . 95 83 . 89 89 . 25 90 . 31 88 . 60 88 . 40 89 . 04 87 . 06 86 . 52 79 . 79 88 . 74 83 . 169 60 55 . 00 70 . 48 80 . 24 81 . 67 85 . 48 87 . 14 82 . 86 88 . 34 88 . 81 87 . 14 77 . 82 84 . 76 80 . 7910 60 60 . 95 70 . 95 70 . 48 67 . 86 76 . 43 85 . 24 88 . 34 91 . 43 89 . 76 89 . 29 85 . 48 89 . 76 80 . 5011 60 56 . 72 70 . 08 81 . 75 87 . 88 88 . 15 88 . 18 83 . 41 87 . 94 87 . 04 88 . 92 83 . 28 89 . 57 82 . 5712 60 56 . 35 66 . 67 79 . 68 85 . 87 89 . 66 87 . 43 88 . 71 89 . 26 87 . 70 85 . 90 79 . 81 89 . 39 82 . 2013 60 52 . 46 72 . 14 83 . 99 88 . 71 90 . 40 88 . 57 89 . 82 90 . 63 89 . 63 88 . 12 86 . 51 85 . 82 83 . 9014 60 59 . 53 71 . 67 80 . 95 85 . 07 89 . 05 91 . 19 90 . 71 90 . 95 87 . 62 90 . 95 86 . 91 91 . 43 84 . 6715 60 47 . 14 58 . 57 74 . 28 82 . 14 87 . 14 90 . 17 88 . 10 89 . 29 86 . 43 88 . 81 83 . 33 87 . 62 80 . 2516 60 54 . 52 75 . 24 88 . 10 92 . 62 90 . 95 89 . 76 88 . 10 88 . 81 86 . 43 87 . 15 79 . 76 88 . 10 84 . 13__________________________________________________________________________ table k______________________________________shell weight ( grams / egg ) no . of avg . fordiet eggs week 1 week 2 2 weeks______________________________________9 - 12 240 5 . 58 5 . 54 5 . 5613 - 16 240 5 . 67 5 . 63 5 . 659 and 13 120 5 . 52 5 . 60 5 . 5610 and 14 120 5 . 59 5 . 55 5 . 5711 and 15 120 5 . 68 5 . 60 5 . 6412 and 16 120 5 . 70 5 . 59 5 . 659 60 5 . 45 5 . 54 5 . 4910 60 5 . 60 5 . 54 5 . 5711 60 5 . 63 5 . 53 5 . 5812 60 5 . 64 5 . 54 5 . 5913 60 5 . 60 5 . 65 5 . 6214 60 5 . 59 5 . 56 5 . 5715 60 5 . 73 5 . 64 5 . 7016 60 5 . 76 5 . 64 5 . 70______________________________________ table l__________________________________________________________________________feed consumption ( grams per hen per day ) no . ofweigh - week week week week week week week week week week week week avg . fordiet ings 1 2 3 4 5 6 7 8 9 10 11 12 12__________________________________________________________________________ weeks9 - 12 240 48 . 46 99 . 99 109 . 73 119 . 50 122 . 02 125 . 81 121 . 58 120 . 55 119 . 90 116 . 19 127 . 07 126 . 87 113 . 0613 - 16240 46 . 83 99 . 44 108 . 18 115 . 65 117 . 85 120 . 77 118 . 26 118 . 37 118 . 88 115 . 16 123 . 32 127 . 25 110 . 899 and 13120 50 . 38 102 . 66 111 . 29 119 . 56 122 . 97 122 . 55 121 . 86 120 . 09 119 . 88 114 . 09 126 . 58 127 . 97 113 . 4110 and 14120 51 . 39 98 . 54 106 . 64 115 . 63 121 . 17 123 . 85 120 . 33 120 . 67 120 . 22 117 . 38 127 . 20 128 . 18 112 . 5211 and 15120 40 . 78 95 . 91 106 . 74 116 . 19 116 . 49 120 . 14 115 . 64 115 . 23 115 . 71 112 . 91 123 . 17 123 . 68 108 . 5512 and 16120 48 . 02 102 . 77 111 . 14 118 . 91 119 . 03 124 . 61 121 . 86 121 . 83 121 . 32 117 . 33 125 . 82 128 . 41 113 . 429 60 55 . 36 107 . 40 116 . 61 123 . 85 126 . 99 124 . 25 126 . 59 124 . 45 121 . 78 115 . 12 127 . 93 129 . 53 116 . 6610 60 50 . 04 94 . 97 102 . 57 115 . 92 121 . 49 126 . 62 122 . 74 123 . 44 122 . 81 118 . 76 130 . 94 129 . 54 113 . 3211 60 41 . 59 96 . 84 109 . 08 117 . 39 116 . 79 120 . 14 225 . 64 113 . 21 115 . 28 111 . 69 123 . 85 121 . 46 108 . 5812 60 46 . 84 100 . 76 110 . 66 120 . 83 122 . 83 128 . 23 121 . 34 121 . 08 119 . 75 119 . 21 125 . 55 126 . 94 113 . 6713 60 45 . 40 97 . 91 105 . 97 115 . 27 118 . 95 120 . 85 117 . 12 115 . 74 117 . 97 115 . 06 125 . 23 126 . 42 110 . 1614 60 52 . 74 100 . 10 110 . 72 115 . 33 121 . 04 121 . 08 117 . 92 117 . 90 117 . 63 115 . 99 123 . 47 126 . 82 111 . 7315 60 40 . 00 94 . 98 104 . 39 115 . 00 116 . 20 120 . 14 115 . 63 117 . 25 116 . 14 114 . 14 122 . 50 125 . 90 108 . 5216 60 49 . 20 104 . 78 111 . 62 116 . 99 115 . 22 121 . 00 122 . 39 122 . 58 122 . 90 115 . 46 126 . 08 129 . 88 113 . 17__________________________________________________________________________ table m______________________________________body weight ( grams per hen ) no . ofdiet no . weighings difference______________________________________9 - 12 240 218 . 0013 - 16 240 219 . 469 and 13 120 228 . 2510 and 14 120 219 . 5011 and 15 120 205 . 3312 and 16 120 221 . 839 60 239 . 5010 60 228 . 3311 60 179 . 6712 60 224 . 5013 60 217 . 0014 60 210 . 6715 60 231 . 0016 60 219 . 17______________________________________ table n__________________________________________________________________________egg weights ( grams per egg ) no . of avg . fordiet weighings 1 week 2 weeks 3 weeks 4 weeks 6 weeks 8 weeks 10 weeks 12 weeks 12 weeks__________________________________________________________________________9 - 12 240 51 . 42 51 . 86 53 . 42 54 . 07 55 . 48 56 . 49 57 . 57 58 . 72 58 . 8813 - 16240 52 . 57 53 . 90 55 . 04 55 . 94 57 . 21 57 . 88 58 . 79 59 . 82 56 . 399 and 13120 52 . 05 53 . 10 54 . 82 55 . 18 56 . 38 57 . 19 58 . 35 59 . 30 55 . 8010 and 14120 52 . 24 52 . 38 53 . 18 54 . 36 56 . 24 57 . 29 58 . 37 59 . 29 55 . 4211 and 15120 51 . 28 52 . 31 54 . 13 55 . 04 56 . 18 56 . 87 57 . 53 59 . 00 55 . 2912 and 16120 52 . 43 53 . 73 54 . 78 55 . 45 56 . 59 57 . 39 58 . 48 59 . 48 56 . 039 60 51 . 30 52 . 08 54 . 25 54 . 49 55 . 39 56 . 71 57 . 71 59 . 08 55 . 1110 60 51 . 72 51 . 05 52 . 06 53 . 10 55 . 54 57 . 00 58 . 01 59 . 20 54 . 7911 60 51 . 31 51 . 81 53 . 95 54 . 35 55 . 38 56 . 09 56 . 65 58 . 38 54 . 7412 60 51 . 36 52 . 50 53 . 51 54 . 36 55 . 62 56 . 18 57 . 91 58 . 21 54 . 9613 60 52 . 79 54 . 11 55 . 49 55 . 87 57 . 37 57 . 68 58 . 99 59 . 53 56 . 4814 60 52 . 76 53 . 71 54 . 30 55 . 62 56 . 93 57 . 58 58 . 74 59 . 37 56 . 1315 60 51 . 25 52 . 82 54 . 32 55 . 74 56 . 98 57 . 64 58 . 41 59 . 62 55 . 8516 60 53 . 51 54 . 96 56 . 05 56 . 53 57 . 566 58 . 60 59 . 04 60 . 75 57 . 12__________________________________________________________________________ a review of the test data in tables p and j through n shows that substantially the same results were obtained as those in tables b through h . in a preliminary study of a relatively few laying hens with one percent zeolite in the diet it was indicated that the relative ranks of zeolites in improving shell strength were as follows : ______________________________________rank shell strength______________________________________1 zeolite a2 synthetic mordenites3 synthetic zeolite x4 natural erionite5 natural clinoptilolite6 synthetic zeolite y______________________________________ in shell strength , the controls were inferior to or equal to the poorest of all the zeolites . the later studies clearly show that zeolite a is effective in increasing shell strength . some increases in shell strength using mordenite should also be expected . the term poultry includes all domestic fowl , namely chickens , turkeys , ducks , geese , and the like . corn is the principal diet for most lying poultry . a feed formulation comprising by weight percent the following is desirable : ______________________________________ weight percent______________________________________corn 50 - 75soybean meal 10 - 30calcium carbonate 4 - 10zeolite a 0 . 25 - 4 . 0______________________________________ calcium carbonate is usually in the form of natural limestone ground to a suitable particle size , but sometimes oyster shells which have also been suitably ground are used . it can be appreciated that a wide variety of nutrients or foods may be included in the diets of layers or poultry laying hens . in a controlled environment , the hens are only exposed to desired foods or food products . a typical laying ration composition contains the following : ______________________________________ weight percent______________________________________crude protein - not less than 16 . 0crude fat - not less than 2 . 5crude fiber - not more than 7 . 0calcium ( as ca ) - not less than 3 . 1calcium ( as ca ) - not more than 4 . 1phosphorus ( p ) - not less than 0 . 5iodine ( i ) - not less than 0 . 0001salt ( nacl ) - not less than 0 . 3salt ( nacl ) - not more than 0 . 9______________________________________ the foregoing composition is obtained from or included the following ingredients : grain and processed grain by - products . includes corn , corn hominy , corn germ meal , barley , millet , oats , rice , rice hulls , rye , sorghum , wheat and wheat shorts . these are among the energy ingredients , mostly carbohydrates with some proteins . plant protein products . includes soybean oil meal , barley malt sprouts , coconut meal , corn distillers grain , corn gluten meal , cottonseed meal , pea seed , potato meal , peanut meal , rape seed meal , sunflower meal , wheat germ meal , brewers &# 39 ; yeast . all of these are protein sources . roughage or fiber . includes dehydrated alfalfa , alfalfa hay , alfalfa leaf meal and pasture grasses . these are all fiber sources . animal and fish by - products . includes blood meal , blood flour , dried buttermilk , dried whey , dried casein , fish meal , dried fish solubles , liver meal , meat meal , meat meal tankage , bone meal and dried skim milk . anchovies , herring and menhaden are sources of fish meal . minerals and synthetic trace ingredients . includes vitamins such as b - 12 , a , pantothenate , niacin , riboflavin , k , etc ., dl methionine , choline chloride , folic acid , dicalcium phosphate , magnesium sulfonate , potassium sulfate , calcium carbonate ( limestone , oyster shells ), salt , sodium selenite , manganous oxide , calcium iodate , copper oxide , zinc oxide and d activated animal sterol . molases and animal fats are added to improve palatability and to increase or balance the energy levels . in general , a feed composition for poultry laying hens should preferably contain by weight percent the following : ______________________________________ weight percent______________________________________crude protein - at least about 14crude fat - at least about 2crude fiber - not more than about 7calcium - about 2 . 7 to 4 . 1phosphorous - at least about 0 . 05iodine - at least 0 . 0001sodium - about 0 . 1 to 0 . 4chlorine - about 0 . 1 to 0 . 5zeolite a - about 0 . 25 to 4 . 0______________________________________ the foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the illustrated process may be made within the scope of the appended claims without departing from the spirit of the invention .
a method of improving the quality of egg shells of laying poultry or laying hens without deleterious effects on the contents of the poultry egg shells by adding a small amount of zeolite a to the feed of the poultry , and a poultry feed for laying hens containing zeolite a .