I have a 2yo black australorp who is sick. She has been isolating herself from the flock, looking lethargic for the last few days. She was our chick who had pasty butt, and she's always been smaller than our other 3 hens (all BAs). I've noticed white goo coating her feathers under her vent. This has been going on for some time, and I never took much notice, because she seemed healthy and it wan't too bad. This weekend the discharge has gotten worse. Friday evening she was standing in the middle of the yard straining, like she wanted to lay an egg. I picked her up and found that she had a slightly prolapsed vent. So I brought her in, gave her a bath and pushed the tissue back into her vent. Saturday morning she was looking pretty chipper and complaining about her confinement, so I let her back out. I think she laid an egg. Not totally sure if it was her, but I went outside immediately after hearing an "egg song" and she was in the nesting box, moving the egg around with her beak. Yesterday we noticed she was lethargic again, so I brought her back in, gave her another bath to clean off all the poo, and trimmed all the feathers around her vent. When I flipped he back to a standing position, a stream of yellow stuff came out of her vent. It looked suspiciously like egg, so I put on a glove and felt inside her for broken egg shells. I didn't find any (but I'm totally new to nursing chickens and I don't know how far back to reach in.) The vent itself is a healthy pink and hasn't prolapsed again. It does bulge out when she breathes, and her breathing is kinda labored. I've kept her in a large dog cage, covered with towels to monitor her. She's panting and pooping small amounts of runny, dark green, mixed with whitish yellow. She doesn't have much interest in food or water. We got her to eat a small leaf of kale and she gobbled up a spoonful of vanilla yogurt (didn't have plain yogurt on hand) but she ignores the feed and water. The rest of the flock is scratching around the backyard acting like normal chickens. When I pulled her out of the coop last night to bathe her, I noticed that she doesn't sleep on the roosting bar with the others. She was on the floor under their tails, just sleeping on the layer of sweet PDZ that I keep under them. It's a wonder she's not always covered in chicken poop. I haven't taken any pics, so I'm trying to include every detail I can think of...I went to the feed store this morning and they gave me a bottle of Sulmet, but I haven't given her any. After perusing the forums, it looks like vent gleet to me and antibiotics seem like the wrong way to go. This is my first time having a sick hen. She's the kids' favorite so I don't want to cull her unless I have to. Any advice?