This was our first year in letting a clutch hatch with the hen. No problems hatching, but one by one we seem to lose our baby chicks and not sure why. They all seem to lose their feathers around their bottoms before dying. We watching for clogging and made sure they were clean, but it didn't seem to help. They acted fine up until we would find them. Seem to happen at any age - couple days old up to 8 weeks old. Would love any help we can get. Live in Washington state and its been very wet and rainy this spring, but they all had shelter to stay warm and dry.