It's been a rough winter in PA, but my birds (until yesterday) have done great in the snow and cold as they've always done. Yesterday I found two dead Leghorns - one outside in the run and the other in the coop. There were no signs of struggle, no blood, nothing, so I'm confident this is not a predator problem. They are also healthy... no colds, mucus, coughs. The coop was just cleaned about 2 weeks ago. Today when I fed them I found my beautiful RI roo dead on the coop floor. Again, no struggles, healthy, just gone. I can not find out what caused their deaths! The ONLY thing that has changed in my routine is a switch to a different brand of food. There is no mold in the food (that I can see), but I'm so skeptical considering that I began feeding this brand on Thursday, and now have 3 dead birds. Does anyone have any suggestions? I think, to be safe, I will take the food back and explain what happened, not to accuse or point finger but just as a precaution. I can't think of anything else it would be. Thanks!