A lot of the food trials use really novel proteins like kangaroo (and sometimes rabbit). I always thought that was kind of funny, but it seems to work since most dogs here have never had kagaroo!
Zignature actually has a kangaroo flavor! And I believe Nature's Variety has rabbit but NV is pretty expensive.
It definitely is funny but I can see how it would work!!!
Duck isn't exactly novel but a lot of dogs have never had that either, a lot of foods use chicken, pork, beef type thing. Although some dogs are allergic to all poultry.
I think there's another brand that does kangaroo and lentils but i cant think of its name