I am probably wasting time/food/energy on this one bird, and I can’t help it - still want to have thirty-six slaughtered chickens come the end of July :) I put the “sick” chick back in the shed with her own water and food. Tried feeding her a bit myself and that seemed to perk her up, but I doubt it’s anything more than temporary.
If it’s a leg problem, then I doubt she’s been getting enough to eat. If it’s coccidiosis then this should hopefully quarantine it. I am now continually worried about the birds that don’t move when I bring out new food; will have to keep an eye on all of them.
In the worst case, if she dies, here are some pics
Update (June 25): She made it through the night, and it is seeming more like a leg problem. She's able to hobble enough to turn around from time to time, and will still eat and drink a bit.