a few months back i had a chicken die without warning, all of the other chickens have been fine since then, but then yesterday another one was dead. now ive noticed that none of my living chickens are eating or drinking as much as they were before. and this morning, reaching under one of them to get eggs, i felt that her breast bone is very prominent. so then i started feeling all of them and they are all very prominent. now i swear before that i could just barely feel their breastbones. so im guessing they are losing weight. does anyone know what this could be? they all act fine, and if i let them out to free range then theyll scratch around, but in their pen they are barely touching their food, water and scratch? i just can't let them out to free range right now because we've had a coyote coming around. any ideas?? thanks!