Chances are slight that Julius is a frog. We doubt that Sandra left the milk. It is highly unlikely that Emily is a wolf. It is unlikely that if either 'Sandra left the milk' or 'Emily is a wolf' but not both then Jessica is a sheep. It is certain that if 'Sandra left the milk' or 'Emily is a wolf' or both then Greg is a frog. There is a better than even chance that if 'Sandra left the milk' or 'Julius is a frog' or both then Bernhard is a swan.
It is probably not the case that 'Emily is a wolf' or 'Sandra left the milk' or both.
It is probably not the case that 'Emily is a wolf' or 'Sandra left the milk' or both.
It is highly likely that 'Emily is a wolf' or 'Sandra left the milk' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.1::factA.
  0.2::factB.
  0.05::factC.
  %hop1
  0.2::factX:-xor(factB,factC).
  1.0::factY:-or(factB,factC).
  0.6::factZ:-or(factB,factA).

  %hop2
  conclusion:-or(factC,factB).

  query(conclusion).
  
'Emily is a wolf' or 'Sandra left the milk' or both.