Yes Bunnies and Rabbits do fart.
I've been around my own bunnies that farted and it smelt pretty bad although not as bad as a human fart or a dog fart.
Sometimes the bunnies fart may not produce any sound or much if any smell but sometimes you can hear the fart and even smell the fart as well.
Bunnies digestive systems are a bit different than a dogs or humans digestive system but they do produce gas in their stomach which they need to relieve through farting.
Most animals do fart just like humans do and sometimes it can be heard and smelt while other times it may not be noticed.
But bunnies and rabbits can and do fart.