How long to regrow toe nail?

Chicken lost toe nail about a wk ago was limping and not moving much for a few days and standing on one leg a lot outside patio door but is quite happily running round with the other two now but still keeps coming to patio door and stands on one leg and appears a little lopsided on the perch. How long for nail to grow back and shld she still be on one leg? Does this mean she's still in pain or having problems with it or will it settle when the nail grows back (assuming they do)