Hi all! I have a Isa Brown hen, who is a little over a year old. Starting yesterday, she has been sitting mostly, when she gets up she acts like she cannot support her body weight. I thought she was egg bound but today we got six eggs (we have 6 hens so that seems right). Her comb is bright, she is drinking and eating, her tail feathers aren't drooping, some of her side wings are droopy... just not walking around and acts so tired. We've been giving them Oyster Shells periodically, and today we added some ACV to their water. We've had the chickens for over a year now and never had this happen before. All of the other birds are acting fine. Any ideas??