Either they grow out of it as the bones get stronger, or they stay gimpy. Lots of times, the other birds will pick on, hurt, kill a bird that is "not normal".... survival of thhe fittest kind of thing. You can attempt to fix it if you are so inclined, with a brace and bandaid.
I had a chuker chick with a clubbed foot and broken toes. It was walking on its "ankle". We straightened the foot and wrapped it with vet wrap for 3 days and the foot then fixed itself. Their bones are so tiny and malleable when they are young, that they break eaasily, but mend just as easily.
Here is a pic of the brace-job on the little 2 day old chuker. It is NOT easy to do properly, as the little legs are SOOO tiny, but my DH and I worked together and I can't even tell now (the bird is about a month old) which one had the bum foot. You can look up braces and what to use/ how to do it. I know there are posts about it, as someone on here showed me a link....but I don't hhhave it offhand. You need to make sure not to wrap too tightly. You could use a small piece of cardbboard/ cardstock, cut in teeny foot pattern to tape on.....but it will be difficult.