Hey,
I would suggest trying crickets man! Racers of all ages big and small will take crickets! Try that first before anything else, if not that try pinks, if not that try lizards. Try the lizards as a last resort, be better to have them on crickets instead of lizards. I avoid lizards in any way possible. But there are some coluber that just want only lizards. And in that case for a healthy snake give them what they want. Just make sure you freeze and thaw the lizards so they are parasite free! I have heard the Coluber c. constrictor are a lot easier to work with, than Coluber c. priapus. Those guys are very hard to work with, I had one big adult female that ate mice. Most are small and don't! You have to really look at why c. constrictor would eat mice over c. priapus. The Northern tends to extend as high as the east coast. There are very few lizards up that way, so diets would consist mostly of rodents and insects! Down in Florida for example, there are a lot of lizards there! I am not saying Northerns don't take lizards, but what I am saying is, They are more likely to take them because of their geographic location.
So try crickets first, I am confident they will take those. If not try pinks. If they just wont take anything offered. Assist feed them because one of the only ways to raise coachwhips is assist feeding for the first year! I hope I have helped! William Huntsman
Green Pine Museum