As Dan mentioned, any broadhead will do, but most guys that bowhunt turkeys use larger diameter mechanicals.  I havent turkey hunted with my recurve yet, but was planning on using the Magnus Bullheads when I decide to give it a try.  That way, I don't run the risk of wounding a bird - he's either dead right there or its a clean miss.  
Also, the larger cutting diameter gives me a better chance of hitting him.  I have practiced with them out of my recurve before and they fly great, I just don't have quite enough confidence in my recurve ability yet to give it a shot..