Please give it lots of time. It takes time for them to learn to walk on two legs - it will take time for it to learn to get around with it's third leg but it may surprise you and do just fine. While it's hard to watch it is a fact of life that we can't all be perfect, in fact none are really perfect, it's all in the viewpoint of what perfect is.
I have a chick that has a deformed leg and she is 8 weeks old and gets around by hopping on good leg. I'm thinking of having the bad leg amputated because it's in her way, sticking out from her side or over her head and throws her off balance sometimes or gets hung up in things and keeps her from being able to take a dirt bath and roll on ground. But I wouldn't put her down for her deformity. In her case I'm just going to help her live better with it.
In your case, you have something really special as a result of an odd experiment. I would have never thought of trying to incubate store bought frigerated eggs. I hope the rest all hatch to be normal/perfect. Let us know and keep us posted.