I have chicks about two weeks old now and one of them started falling over and by the end of the day her legs just didn't work at all. I took her back to where we bought them and they said it was probably splayed legs and I should cull it. But I did some reading here on BYC and found a thread about vitamins. I went out and purchased the Enfamil Poly-Vi-Sol vitamins, put her in her own little box, and started adding a dropperful to her water, plus a couple drops right into her mouth. It's day three and she's back on her feet. I'm totally stoked and just wanted to share that with everyone. Just because the chicks start falling over, or their legs get weak, doesn't mean you have to cull them. Hopefully this info can help your chick if she's having leg problems. Good luck!