This seems to be quite common, and is known a spraddled legs. Different people have different ideas on how to deal with this. Some people cobble together a system of rubber bands or wool and bind the legs for a day or two in the hopes that it comes right. I dispatch them if they cannot stand after 24 hours in the hatcher. Having a very grippy surface in the hatcher seems to help, and I now hatch mine on a rubber faced mat with a fine interlocking grid of tiny rubber treads. It is made for use on the ramps of horse boxes so horses do not slip as they go in and out of the box, and you can sometimes buy offcuts suitable for the hatcher floor. Even this precaution is not guaranteed to help in a bad case, but slippery surfaces definitely exacerbate the problem.