My family got 10 buff orpington's from rural king, we do the same stuff we've done to care for them for 15 years but this year they're falling off one by one. Just last night one was standing with her eyes closed and was pushing her head up and forward a little and open and closing her mouth, she was dead this morning. The others we are unsure what happened over night but with her we are down to five... We're not sure what's happening! I'm thinking it might be the food since that's the only thing that changed but I couldn't find anything bad about it, its natureserve chick starter. Any help on what's happening would be great.