I’m thinking this isn’t going to turn out okay

[Chef JimmyJ]

Try cutting away all the feathers from the lump to the screw. There is, what looks like, a small hole to the right of the lump in the pic. This may be the entry point, which would be better news than, if she ate it. You may even able to see/feel more with the area cleaned up...JJ

 

[EggWalrus]

The head does not feel anywhere near the surface—I can’t feel it with my fingers.

Try pushing the screw to the side, so it lays flat against the birds skin. If it lays flat easily, the screw head may be just under the skin. If it doesn't want to lay over, the head could be deep.
It definitely looks like a sheet rock screw and if you've ever used them you know how bad they are about breaking if used in wood. It could be half a screw without a head. Have you tried to finish screwing it out of the bird? Try turning it counter clockwise, it may screw right out.

 

[EggWalrus]

PS
I wouldn't cut the screw off. The remainder could go back in and cause trouble. I would make a small incision about 1/2 inch long, look in and see if it goes through to her crop. You won't need to stich up a small 1/2 inch incision in just her skin. There are a couple of threads on crop surgery / repair that are straight forward and easy to perform. It's an easy common little "operation"and probably the safest option for the bird.
Good luck!

 

[moniquem]

I would pull it out, she can't be comfortable with a screw dangling from her body.

Trim all the feathers down to the skin so you can see what your dealing with, make a little incision and work it out. Chickens have healed from much more dramatic wounds than that.

 

[Fishkeeper]

In case it hasn't yet been addressed- I guarantee you she is in pain. Prey animals are very good at hiding their pain, but this is the sort of thing that hurts.

 

[Tesumph]

How interesting!
I can’t imagine a scenario where a screw head becomes lodged under the skin from the outside. Having seen a chicken of my own grab a screw and swallow it whole in front of me, I find it very believable that she swallowed it and it perforated through her skin partway down the digestive tract. It’s not incredibly uncommon to see perforations from eating sharp objects, it’s just that usually the foreign objects don’t get lodged in the skin and scarred down while poking out of the body.

That being said, I would not cut the screw off at the base. It will very likely fester under the skin as the body tries (and fails) to push it out and, best case scenario, you’ll be back here in a couple of months to learn how to express a nasty abscess.

If it were my hen, I would first pluck all the feathers in a large margin around the screw. Manipulate the screw and see where you can best feel the head under the skin. Keep in mind that scar tissue holding it in place will make it feel deeper than it actually is.
If I could feel the head under the skin and felt like there was no underlying infections or other complications (major blood vessels, etc), I would cut it out. A small incision and carefully manipulating the screw around would only leave a tiny hole that would heal quickly if it was properly maintained.

The biggest issues I would expect from that is 1) infection, which could very likely happen in any scenario, and 2) if the incision reaches intestines/stomach, then it could scar down onto the body wall or another organ. This probably wouldn’t cause much trouble anyway, but maybe there would be issues with digestion later down the road.

 

[AmyJane725]

Yeah, I'm in the "it needs to be fully removed" camp. I think you're going to have a hard time cutting it flush to the skin, and even if you did, that loose end could cause problems of it's own. If it does get (back) into the digestive tract it could perforate something or cause an obstruction. At least this way you have access to the entire piece. I'd just make a little incision and then slide a currette (or some other skinny, not sharp item) down the sides of the screw to detach any tissue that's holding onto it, and just remove it.
You could even use superglue to close the wound if you're not comfortable leaving it open.

 

[ChickNanny13]

Dry wall screw was the first thing that came to mind, short one (thankfully) and I'm speculating that lump maybe the head. As someone said, it stuck into her when she laid on it, went in side ways and came out.

I agreed cutting it at the skin but then reading through the whole thread, good points were made about why it may not be a good idea. It's hard to figure what to do, we're all not there to see and we all have different levels of experience in "surgery".

In the last picture, there's some brown or reddish brown stuff on the screw towards the skin. Is it rust or something from inside? The more I look at the pics, think I'd get someone to help, load up on antibiotic and disinfectant, make a small incision on the skin a to get it out. Super glue the incision close or some fast stitching.

Is there anything that can be given the chicken for pain? Baby Aspirin? I'm no expert and I feel for the OP, having to decide which way to go.

 

[Tesumph]

Dry wall screw was the first thing that came to mind, short one (thankfully) and I'm speculating that lump maybe the head. As someone said, it stuck into her when she laid on it, went in side ways and came out.

I agreed cutting it at the skin but then reading through the whole thread, good points were made about why it may not be a good idea. It's hard to figure what to do, we're all not there to see and we all have different levels of experience in "surgery".

In the last picture, there's some brown or reddish brown stuff on the screw towards the skin. Is it rust or something from inside? The more I look at the pics, think I'd get someone to help, load up on antibiotic and disinfectant, make a small incision on the skin a to get it out. Super glue the incision close or some fast stitching.

Is there anything that can be given the chicken for pain? Baby Aspirin? I'm no expert and I feel for the OP, having to decide which way to go.

Yes, aspirin can be given at 25mg/lb.

I’d be tempted to leave the incision open as long as possible to encourage draining and avoid an abscess forming, but it really depends on if the intestines or stomach are damaged or not.

 

[AmyJane725]

Is there anything that can be given the chicken for pain? Baby Aspirin? I'm no expert and I feel for the OP, having to decide which way to go.

Aspirin and Meloxicam are the two meds I know of that are ok for chicken pain management. I've heard that vets do use lidocaine sparingly and it doesn't kill the birds. OP would have to decide if she was comfortable putting a little dab over the closed surgery site or not.