I think the man himself, JRR Tolkien, came up with that one.
To quote Wiki google search: A team of twelve Rhosgobel rabbits are known to have been of use to Radagast the Brown, as they pulled his sleigh. They were first seen carrying Radagast from Rhosgobel after his encounter with the Giant Spiders, through Mirkwood to Dol Guldur following the trail of the Giant Spiders.
And now we know where Radagast ended up - Ozark Wizard on PSD!
Well, wiki Google aside I certainly recall no mention of any such rabbits in any of the four volumes comprising The Hobbit or The Lord Of The Rings, and unless such an update was made previous to the Jackson directed Hobbit trilogy I would be suspicious at best of it, it is possible that in Tolkein's private letters, or in the Silmarillion that mention was made, haven't read that, but I still consider it creative license by the writing team Jackson worked with to produce the film.
No really related but kind of... This morning on Missouri meerschaums website corncobpipedotcom this was listed as for sale. It was the LEAPS pipe of the year 2020. I was able to add it to my cart but later when I went to purchase it, gone and all history links go to 404 not found page. What the heck?
When we had MM do our PSD & PSF POYs the had a hidden ordering link which we only released to members. I'm kinda guessing their web guy inadvertently made it public. Once it was noticed they changed it. At least that is my theory.