Sick Buff-need advice

Hi all,
Could use some advice on a sick Buff Orp. Got her ( I think its a she) from someone who did 4H and sells her birds about 2 months ago. Approx age is 3 mo. I don't know the hatch date she couldn't remember exactly.

Anyhow, bird has been doing just great. She came with another little silkie friend and the silkie is fine. They have been separated from the rest of our flock since we got them. Hubs is building a new coop for them. This morning when hubs went out to feed and check them she was limping on her foot. He brought her in the house and we cleaned her feet. There was some stuck droppings on them but I didn't see anything out of the ordinary (like bumblefoot) One pad might have looked a bit puffy but not much. No cuts or scrapes noted. She is kind of hunched up at the shoulders and doesn't want to stand on it, she's just sitting on her rump and her feet are out in front of her.

We do have an avian vet here. I have never been there before and called today. Its over $100 just to have her looked at, not counting any tests. I'd hoped they might offer some advice on what I could try to do at home before having to bring her in. They said it could be anything from liver failure to leg or foot problems. We just do not have $100 to bring her in to find out there's nothing we can do.

I'm just sick about this. These birds are our pets. Can anyone think of anything else I could do? She looks ok otherwise, eyes look fine, she ate fine yesterday. And she's usually quite active. It seems this happened overnight. She is in a separate area, their bedding is hay and is changed daily. She does free range but hasn't in a few days because we've gotten bad rain. I can't imagine what could have happened to her.