Every month or two I find one of the pullets dead in the coop. None have any signs of illnesses prior to finding them below the roost. It happens every 4-8 weeks. None of the others appear sick and all are laying well. They are about 10 months old. I usually find them in the morning but today I find an EE dead in the afternoon when I went to collect the eggs. She appeared fine this morning. This pullet had not started laying yet. Any ideas?