We have one of our baby chicks with swollen abdomen - it looks like a half egg yolk size thing, soft to touch. He does not seem to be in pain, drinks normally, but eats very little. He is lethargic most of time and stays under heat lamp, sleeping on his feet, while other chicks are actively running around. His bum has been clean all the time, and his droppings are normal in color and consistency (I only noticed him pooping twice, not that I watched him all day). There are no lesions anywhere, vent looks totally normal, no swelling there . Can you help to determine what this may be? Is he going to die? I am really worried about the poor fella... He is smaller than anybody else. Here are a few pictures.