Chicken uninterested in moving much or eating anything but worms

[Wings and stings]

My cream leghorn is 7 months old. She was always a runt compared to the other looking to be half the size. As a baby she had a piece of string stuck in her mouth that I had to pull out and would get grass stuck in her mouth that I’d have to pull out several times when she was old enough to go outside.
A couple months ago I thought oh she’s caught up in weight. She was no longer inches shorter than the other leghorn. Well I picked her up a few days ago and I was shocked she weighs nearly nothing. Just all feathers and bones. Maybe 2-3 pounds at most.
She’s recently not been interested in treats. She maybe goes for them eventually but very sluggish about her interest level. so I kept an eye on her and she’s been going to bed while everyone is still out for a while. Two days ago I saw her standing off by herself not doing anything, just standing there. Yesterday I brought her inside in a dog crate and gave her some rooster booster water. She drank a little bit while I watched. One at a time I offered her food, mash, vegetables and greens the rest of the flock loves. She looks at like she wants to eat but doesn’t. She snatched up two tiny pieces of strawberry but when I gave her more she just looked at them closely. She hardly made a sound all evening and morning in the crate and hardly moved much. This morning I offered her a worm. She picked it up and shook it for 10 minutes not liking that a pine flake kept sticking to it. We offered her others that were on a plate and she gobbled them up. Then pooped clear water. Put her outside with a few of the other girls and she just stood there while they raced around gobbling up worms. If we presented her worms she would look at them a while and then eat them but wasn’t seeking them out herself.
Nothing about her physically seems to be amiss except her comb is a bit lighter than the rest of the girls and has a few little black dots from the extreme cold in feb? A friend with chickens came and inspected her and said not egg bound, not water belly, crop felt fine, no mites. She looks healthy it’s just her behavior.
The rest of the flock has no issues. None have been sick or anything since we’ve had them.
If it’s worth taking her to a vet I will.
Photo from a few days ago. I’d be surprised if she’d even get in the tire now.

 

[nuthatched]

She may have a reproductive issue, has she ever laid?

 

[DonyaQuick]

Could be either reproductive issue as above, something like cancer (can cause serious weight loss), or even an impaction that is no longer in the crop an is stuck somewhere further back. A few days is a long time for something like egg-binding but could be late stages of something like cancer.

Hungry and interested in food but unwilling to eat except for a bizarre choice food here or there that they didn't have to run after has been a trait of all of the various impactions I've dealt with. Birds I've had with other chronic issues like reproductive problems had zero interest in food and didn't even want to look at it. The impactions I've seen ranged from being caused by the usual grass/fiber stuff to eating somewhat toxic plants that caused muscle issues and really messed up food passing through the gut. Keeping the bird drinking is extremely important if it's an impaction in the gut past the crop; pipette water to the side of the beak if she stops being willing to drink on her own. Sometimes liquidy will move around the impaction at first, leading to watery or just clear poop for a while before the actual dry mass is passed, which can take days after noticing the bird is off. Impacted birds I've had were sporadically willing to eat small quantities of very wet fruits like grapes or other berries.

 

[AGeese]

Droppings?