Won't pick up a lead all of a sudden, chiropractor needed?

[*Candy*Horse*]

Before I bought my horse from PA, he would pick up both leads fine. Yes he is one sided more, he loves to gallop around and around on his left. Ever since a brought him to NJ form PA, he stopped picking up his right lead totally. I can get it over jumps, but he will not voluntarily pick it up. I've heard many suggestions, and I've concluded before doing anything, I'll get a chiropractor to check him out. Does anyone know any sites online or place that I can find a listing of chiropractors (equine) in New Jersey. (United States)?
Please help me, I don't want to ride him through pain!

[Lgd]

I don't have specific knowledge of chiros in the US but you may be able to get a suggestion from the vet forum on www.ultimatedressage.com Folks on the board are really helpful and most are US based.