Board Thread:General Mod Discussion/@comment-83.94.207.233-20160322140518/@comment-26172435-20160322141729

Usually a single block wall, topped with a single layer of fence or wall blocks is sufficient to keep any rabbits out. Another requirement is that you don't leave any solid grass or dirt blocks open within the fenced arces you wish to use to grow crops. Rabbits will spawn on top of normal gras and dirt blocks. And don't leave the gate open.