Advice needed regarding quail hen with head enlargement

I was out feeding the quail and came across a little hen with a strange looking head. I brought her in and she is away from any males for now. Im pretty sure the sack on her head which wiggles when she moves her head is filled with blood. She doesnt seem to be bothered by it and she can stay with me at least until the blood is absorbed or Im wondering if I should make a cut and drain it? Any advice on this is welcome.

Ouch.. Usually, I'd recommend to drain anything that looks like an abscess, and I think I will this time as well. But if it really is filled with blood, it could be an ongoing bleeding and the pressure from the skin might be reducing the bleeding, which can be a good thing. Or a bad thing, if the bleeding is coming from the brain and is putting pressure on the brain as it can't escape because of the skin.. So, yeah, I'd probably puncture it, but keep something on hand to stop the bleeding once it's drained.

I punctured it in back and drain a bit of blood. There is not much different size but maybe it feels better to her with less pressure. When I palpated it to work blood out I could feel a lump inside almost the size of the bulge on her head. Could that be her brain or would the brain be encased inside her skull. Im afraid of damaging her brain is if was to push too hard. I could consider making an incision to get whatever if in there out but I need to know if you think it could be her brain first. This is so strange. If it is an infection or tumor, I could remove it. Ive done that before on a little quail with a bad sinus issue that appeared as a lump on its head. It was firm though not wiggly like this little girl's enlargement.

I think the lump is most likely pus - possibly stiffened kind of like cheese. She would be dead if her brain was like that.

Im thinking I need to actually make an incision and remove all that is in there then. She is very alert and seems comfortable even with this wobbling bulge on her head.

Yup, I think so too.

You're braver than I am. Good luck with the operation.

I slipped her in a sock with a small hole for her head to come through. I made a small incision across the loser back of the bulge and some more blood drained. I have to force the cheesy mass out and unfortunately it wasnt a clean removal. It came out in pieces. I know I did not get it all but she now has what looks like a small deflated balloon as a hat. I packed the incision point with antibiotic ointment. She is alert and eating but will stay inside with some other quail hens, no males as I dont want any mounting of her so the incision can heal.

Regarding being brave...it is not that as much as I just want to help them if I can. I feel that I must step in and try to help with issues that interfere with them leading a normal animal life.

I had a feeling it was going to be the cheesy kind. I had a horse with a similarly sized swelling on the inside of its lower eyelid. There was a hole in it already when I noticed, but being all cheesy, it didn't come out. And as it was so close to the eye, I didn't dare cut it out myself, so I went to the vet.
At first, the vet thought it was a tumor of some kind - she didn't recognize it as pus at all, before it started flaking off as she touched it. Even though I'd already told her that was what it was.. Anyway, the evil vet dug the entire mass out piece by piece through the already present and way too small hole, with her FINGER, without any kind of sedation. And my poor horse did nothing but trying to turn his head away. What a trooper.
I was thinking she was going to cause a huge amount of tissue damage, doing it like that - expanding the hole with her finger - but she gave us some antibiotic ointment intended for cows with mastitis to put in the hole every day for the next week but after two days there was no swelling left so we couldn't even get to the hole at the inside of the eyelid to apply the antibiotics.