Oh also, do the chickens have grit available at all times? What about oyster shell? Both of these should be available in separate dishes, apart from their regular feed. Is anybody laying eggs? Was this hen laying eggs? If so, how often? You say you feed layer pellets in the morning. About how much do you feed per chicken. Do you watch to make sure each chicken eats? Is it possible the other hen bullied this hen and did not let her eat?