Sounds like spindly leg syndrome. The cause of it really could be several things but I haven't heard of a true scientific cause. It seems to just be one of those things that happen sometimes. It could be a lack of something in the mothers diet. Of course, it's been a while since I kept/bred PDF's. Really, if the froglette can't get around to eat, it should be euthenized. Some do better than others but don't expect it to live a very long life. Sorry I can't give you any good news. The next batch of eggs may be perfectly fine but if you find your pair is throwing spindly babies, I'd rethink continuing to breed them. Good luck.