Agrees exam, then crate.
Wonders if her leg got hurt scuffling with other birds?
My notes on isolation, exam, limpers:
I'd isolate bird in a wire cage within the coop for a day or two....so you can closely monitor their intake of food and water, crop function(checking at night and in morning before providing more feed), and their poops. Feel their abdomen, from below vent to between legs, for squishy or hard swelling.
Best to put crate right in coop or run so bird is still 'with' the flock.
I like to use a
fold-able wire dog crate (24"L x 18"W x 21"H) with smaller mesh(1x2) on bottom of crate under tray.
Then you can put tray
underneath crate to better observe droppings without it being stepped in. If smaller mesh is carefully installed, tray can still be used inside crate.
If limp is really bothering them by inhibiting their normal activities too much, I will isolate them in a crate to 'force' rest for a day or two. Letting them out late in day, an hour before roost time, to give them a stretch and evaluate their mobility, then decide if they need another day and put them back in crate off roost after dark. Repeat stretch and eval the next day until they are better. Keep crate in coop so bird can remain 'with' the flock.