barred2rock
Crowing
I give my dogs, chickens, and quail plain yogurt in small amounts as a treat about once a month, as it helps with the "good bacteria" in their stomach. They've never had a problem, and it was vet recommended for the dogs. I'd be more worried about the high sugar content if the one in question than the close-by expiration date, as my chickens don't get things with lots of added sugar.
Dogs are mammals which can digest dairy, birds are not and can not. How many hens to you see nursing their young?