Scabbed over bump on chicks butt

[Mercimercime]

I have almost four week old chicks, and one of the chicks has this weird bump on her back above her vent. None of the other chicks of her breed have this large bump. It doesn’t have any feathers and looks scabbed in places. Any idea as to what this is? She also has a few completely Bald places along her spine.

 

[Eggcessive]

They all have an oil gland above the tail, but it sounds like she is getting pecked or pecking herself. Try cleaning it and putting a little plain Neosporin ointment on it. How much room do you have for your chicks? Are they getting overcrowded?

 

[Mercimercime]

The chicks have a large portion of our basement, so they definitely have enough space.