Lethargic chicken, empty crop, not eating.

[minichickiedragon]

Hello. One of my chickens, a 5 month old bantam, was standing in one spot and not moving for a while. She's normally difficult to catch but I've had no problem picking her up.
Right now she's inside in a carrier with water. She's mostly just sitting down. Crop is empty aside from a few pebbles. Not interested in eating (tried live mealworms to really entice her but no dice). I used a syringe to get her to drink a bit of water, like a few ml worth.
Vent is not obstructed/puffy. Didn't feel an egg/mass in her when I checked her stomach/rear. Hasn't gone to the bathroom since I took her in. She doesn't have any discharge or discoloration or weird breathing.
I have a small number of birds and the rest are doing fine.
Can anybody please help with identifying what's going on?

 

[Eggcessive]

Has she started laying? How often, and when was last egg? Could she be egg bound? Is her tail position up or down? Is her comb red? Can you mix some water in a small amount of chicken crumbles or pellets and make a mush, then offer that with a little scrambled egg to her beak. Any pictures of her or her next dropping could be helpful.

 

[minichickiedragon]

She has not laid any eggs yet. I checked for an egg/mass but didn't feel anything. Her tail position in the carrier is pretty horizontal right now, but it was downward when she was outside before I took her in. Her comb looks normal.
I'll see if I can try to get her to eat some mush in a moment.
She had two bowel movements while in the carrier. The first one was just liquid and had a bit of mucus. The second one was mucusy (white and pale yellow) with little bits of something black and mushy and it smelled really bad.
The liner absorbed the watery part. The bit of dried insect is from me trying to see if she would eat and is not part of the stool.

She seems a bit more alert than she was earlier and was looking around when I took her out of the carrier previously and for this photo. I added a nesting box pad in case she actually is trying to lay an egg.

Edit: I made some mush and she was eating it well, and drinking water on her own. I also saw her closing her eyes while standing. When I left her she was standing up and eating/drinking a bit.