I have a Buff Orpington mixed chick that I hatched in the incubator about 3 weeks ago. Unfortunately, he hatched in a fairly dirty incubator with an open navel (some other birds hatched before him and I wasn't able to clean it out in time). However, his navel completely healed up and he appeared to be a perfectly healthy baby chick, until a few days ago when a noticed he had pasty butt. I cleaned him up and he seemed fine except for acting a little tired, but the problem is that the pasty butt is not going away and now his butt seems swollen (it’s kind of hard around where the navel is/was and the rest feels kind of tight and squishy). He is also acting more tired, but he is still eating and drinking fine and his buddy seems fine (I got his buddy about 2 weeks ago from a local). Could this be some sort of delayed Yolk Sack infection? He has been like this for a few days now. Other things you might want to know: • It’s just him and his buddy in a brooder like the hatcheries have. It’s a little rusty, but I`ve never had any problems with it before. He has been in this brooder since he hatched and nothing has changed except that I added a chick about 2 weeks ago. • The brooder is in our basement. • I`m getting some more chicks next week and I don’t want to introduce them to these to if it’s something they could get. • There are no signs of an injury • I`m feeding them medicated chick starter. Its kinda hard to tell from the pictures, but here they are anyway.