Not try to sound ugly but I raise Boers Goat and Holland Lops. If you have a complete feed you don't have to give supplements, they will have everything they need.
Lettuce will give rabbit diarrhea. Also be careful giving any fruit sugar isn't good for them. I would recommend ordering Rowes Gold it helps keep their gut right. I give mine a teaspoon everyday, you can give them their feed but they just sit there when you give them the the Rowe's Gold they go...