Hi, I am new to byc and I have had my chickens since May this year. They are wyandottes, red silver and blue My red one has dry white stuff looking like uric acid on her rear end feathers. I washed it off and I did not see any problems with the skin or vent, no redness, nothing. She has also been laying shelless eggs every week or so since she started laying. I have been giving her yogurt laced with oyster shell to try to help her because she avoids the oyster shell. I dont think she has laied an egg for a few days but my otheres havent stopped. Occationaly she smells like rotten eggs so now I am worried there might be something serious going on. dose anyone have any sugestions?