4 week old doe with swollen vent. : Illnesses, Injuries and Parasites

So I have 4 week old litter of Beveren babies. 1 buck and 3 does. The runt is a doe and has bad pinched hindquarters. She will be culled anyway, but I was going to wait so we could get a meal out of her. Today I noticed she feels really skinny, I flipped her to make sure there are no signs of diarrhea. She is pleanty clean but her vent is really swollen and it seems to hurt her when I touch it. Does anyone know what would cause this in a 4 week old? Do y'all think I should cull now incase it's contagious? Thanks!

-- Wed Dec 13, 2017 2:51 pm --

Hard for me to get pics that show how bad it is, but here's one

Thank you Homer! Yes she is very clean and dry. The hutch has an all wire floor, they still have a DRY nestbox. I considered giving her peniccillin already, but she weighs less than 2 lbs and she is a cull anyway so not sure if that would be worth it. Does anyone know how to even make sure so little medicine gets in the rabbit? When I did 10 lb rabbits they got a very small dose and always end up with a few drops on their fur. What are the chances of this spreading to her siblings are mother? Is it safe to have her with them? Also what causes it? I had an older Dutch buck with an extremely mild case just before she was born, but I was very careful to not let it spread to the other rabbits.

If it is vent disease, know that it is very contagious. And in a kit that young, I would be very worried about losing it to diarrhea which often comes with pen G.

Considering it was/is a runt, has weight issues and now this, I would probably cull it now and keep a close eye on the other kits, the doe and the buck that fathered the litter.

Today she is much better, though still a little swollen. Does anyone think it's possible one of her siblings bit her or something? Marinea, yes I should probably just cull her now, she is really cute but I have to cull her sooner or later because of the bad pinched hindquarters

Turns out it is an injury of some kind. The swelling has gone down dramatically, and there is a srcatch on her with a bit of blood on her fur this morning. I will continue to keep an eye on her, but I'm pretty sure it is nothing more than a scratch Thanks Everybunny!
Edit: can't spell srcatch

It's strange to be thankful for an injury, but yay!