Ive read the splayed legs are from slippery surfaces in the hatching area and brooder. I use one of those anti slip mats that you get for your car or chopping boards etc. theybare cheap,so chuck it away after each hatch they get a bit dirty and seem a little porous.
It might be something else though, nutrition of the parents, genetics passed on. Who knows.
shelf liner material... the rubbery kind.