This isn't a burger suggestion, but another trick to make ground chicken/turkey appeal to the meat eaters.
Ground fennel is one of the main ingredients that gives Italian sausage it's distinctive flavor. I mix it with ground turkey or chicken and proceed with recipes. My husband can't tell the difference ... other than commenting it seems less greasy than usual. But taste wise it's fairly close, especially if it's being used as an ingredient in something else like a breakfast casserole.
I also add fennel to plain spaghetti sauce and in my mind at least pretend I'm still having sausage.
I make my own ground chicken by running chicken breast through my food processor. It comes out great and is lower in calories than the ground chicken my grocery store sells (since their ground chicken has more fat in it).