Yes, you can splint the leg. As long as it's set right away chances are really good that it will heal. A couple of Qtips trimmed to size to act as a brace to hold the bones in place should work along with some vetwrap and gauze. The sooner the better while everything still feels like it can be put together. You'll need to wire up something to support her weight and keep her from overworking her other leg for both day and night.
My favorite chick sling (below) of all time comes from someone else -please forgive my not having the name to credit at the top of my aging mind. Of course they shouldn't be in a sling 24/7.
From my broken chick leg experience, at night time he slept really well in a container full of crinkle paper (
https://www.amazon.com/Crinkle-Fill...&keywords=krinkle+paper&qid=1603432064&sr=8-2) - Construction paper weight of paper because it supports their weight and keeps pressure off the bad leg if you kinda dig holes for their legs, then stack enough of it under their bodies so the legs aren't bearing the weight but it's still nice and snuggly. I think any gift wrap section should have it, I just linked to it for a visual reference.
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