Yesterday we noticed one of the hens was acting a little lethargic and had a giggly crop. After some research we ended up flipping her upside down to drain the crop and gave her some yogurt. At that time the other two hens were normal. This morning all three hens were huddled together and nobody was particularly active. We give them yogurt in the morning but today it was untouched about an hour later. Their droppings seem normal. Egg production has been good. Any thoughts on what is going on?