Chick with leg problems

I'm a first time chick owner and learning by trial and error (mostly both). We were lead to believe you could leave a chick in the coop after it hatches and it would be accepted by the flock. Oh, how wrong our source was. Now I have a 21 day old chick cross between a Silky and Brahma that within hours of being hatched another hen got ahold of. I got the chick away from her and separated it and the Silky that is the broody hen. The chicks right leg is bent out at the "knee joint" and to add more problems so is the whole hip joint. (sorry don't know the chicken terminology for their parts yet). The little leg is bent at a 45 degree angle outward. I've tried splinting both around the "thigh" area and the lower leg area with no success and lots of stress for the chick. Also now the left leg is going out to the side possibly to accomodate for the lack of support from the right leg. The chick is eating and gaining weight but now my broddy hen is showing signs of rejecting it (not letting it nest). Any ideas, advice or wisdome would be appreciated. I as second guessing myself about the future of this chick and need some constructive feedback if anyone can help.