text: how come a chickens lay an egg every day? what will be the biology explanation for it? i believe that the process of producing and laying an egg is consuming a lot of resources. why would nature create such a process? it doesn’t seems to be reasonable do you really want to know the answer to this question?  the answer to why chickens lay eggs is in reproduction. just as women have monthly cycles of discarded eggs, so do chickens. the eggs you eat are the bi-product of the reproduction cycle in the form of an unfertilized egg. that red spot you might see on occasion, that's a fertilized egg and was the beginning of a chick but plucked from the nest before it had a chance to mature. in most commercial hen houses where chickens are housed in small cages, there are no roosters.  i don't think chickens lay eggs every day and that is why you would usually need more than one if you want eggs on a daily basis, but chickens do lay often.