It seems to be a mild case of straddle legs, there are now three out of nine like this..what would cause it?
It seems to be a development issue. It's not footing, they hatched on mesh and were transferred to paper towels, they were like this right from hatching, the ones with bad legs had very long hatches from pipping, I think it was hard for them to push with their bad legs.
I have Swedish Flower hens hatching too, they were incubated together and the SFHs are all fine so far.