Help, 10 wk old pullet injured/ stung/ bit, somehow!

[yinzerchick]

Please help, I have a pullet that must have been stung, or bitten by something. She has a swollen neck/head and if very lethargic. I noticed it last evening when I was rounding them all up to go in the run. (they free range during the day) She was outside the fence and looked too tired to come in. I went out and got her, and noticed the swollen place on her head. I took her inside and gave her sugar water via syringe, and she did eat some dampened bread. I took her back out to the coop and put her on the perch. This morning when my husband let them out of the coops and into the runs, she came out and he didn't notice anyone acting off. I went out to give them their morning treat and thought I saw everyone acting fine. However, when I returned a few hours later to clean up, I found her laying behind the coop, lethargic and looking more swollen. I have her in my lap right now, I gave her some water with nutri drench in it, but she is just so lethargic she is sliding off of my lap.

Any suggestions or antidotes?? I can't find any stinger/bite mark/ or other signs of what happened. Help please!
Thank you!

 

[yinzerchick]

Here are a few pics, her neck seems swollen too, like maybe she ate something that was fighting back on the way down??

 

[yinzerchick]

No ideas? Anybody? She's very sleepy, and keeps nodding off. I'm giving her water with a syringe, every hour. She's not eating.

 

[yinzerchick]

She's still acting very lethargic today, and it doesn't look like the swelling is any better. Any ideas would be appreciated! Please...