I've grown oats for my cat herd. I just start a pot with a thick layer of oats, covered with a thin layer of topsoil. Water well and let it sit in the dark for three or four days. When exposed to light the seeds (which are sprouting) will take off and grow quickly.
I wonder if wheat would be similar or perhaps the bunny would like oats also?
I pick up the oat grass seed at one of the local pet stores and have ordered in online in the past.