Hey former neighbor, I grew up in Rowley! My parents still live there. Maybe we can talk business some time, I sold a lot of Thanksgiving turkeys to friends and family down there this year. I'm about 2.5 hours up 95 these days.
Anywho, if the hill is actually close to 40 degrees, I could see it introducing some hazard to CX's once they get bigger and unstable. Heck, my pens are on mostly flat land and they face plant pretty often. Rangers or layers I don't expect would mind too much... but you will when tending to them. May need to get creative with a feeder system as well to keep that up right.
It just sounds like it could be a real burden. It'd certainly be worth trying once if you had free access to the land, but I'm not sure I'd go about renting it without knowing for sure how it would work out. If you would have the option to a long-term lease and could improve the land, and it made business sense, it may be worth terracing. Just a thought.