Our first hatch for this year involved mutt chicken eggs, taken from our starter backyard flock. We hatched on March 7th, and the chicks seemed perfectly normal until about 6 weeks old. We raised them in a brooder that was a large 100 gallon stock tank with hay in the bottom for the first three weeks or so, so there was no sliding or slipping around on sleek newspaper. We then moved them to a larger area in our barn, with wood shavings for bedding. At about six weeks one of them developed splayed legs, and couldn't move around. We ended up dispatching her. Now we have another one that is starting to have splayed legs and getting worse all the time. These birds are fully feathered, and they are now in yet another coop area. I don't think it's germs. We have had them on chick starter feed the whole time. Is there something they are missing missing nutritionally? Or something else we are missing?