I have had 3 chickens up and die in the last week. They were perfectly happy and running around playing one day then sick the next. Then dead. I can't figure out why. They have a half acre lot. They run in. We put them in 2 large hen houses at night. Plenty of fresh water. Wheat grains, crumbles and pellets for food. I give them loaf bread sometimes for treats.and basically most fruits and some veggies. Any suggestions.