I asked a vet recently about ckickens being lactose "intolerant". He said that chickens are not intolerant. There are specific symptoms of intolerence-bloating, gas, diarrhea. Chickens do not have these symptoms. Some chickens handle lactose better than others. His advice is that if your chickens have no problems with lactose than give them milk products. I have fed my girls homemade yogurt, cottage cheese and milk for years with no ill effects. As a matter of fact the first food that my chicks get is yogurt for the probiotics. Someone on BYC accused me of killing chickens by advising people to feed yogurt so I asked someone who actually knew what they were talking about. No worries-feed lactose but dont go overboard.