I was surprised my rabbits liked them because they were a bit spicy. They probably liked them since they are crunchy. Can't tell you if they're good for rabbits or not. Mine will also eat turnips but they won't eat squash.
The various lists of healthy food for rabbits differ on radishes - all agree that the tops are fine, but some say "tops only" without explaining why. I've found other references which say the roots are OK, and none which say they are harmful.
I'd try a small one and see if your rabbits will eat it. If they do, then wait a day or two and see if there's any adverse reaction. If not, then it's probably OK.
I just read about pet rats and radishes and it said in several sites that radishes (roots) cause gas and pet rats cant burp and that is why they should be given rarely in limited amounts. I assume this is also true for pet rabbits I think will not give any radish roots to my rabbits since rabbits have delicate tummies more so than rats.
We have fed our rabbits radishes.....seems to be an acquired taste. Actually, all ate the tops but only a few ate the radish itself. Yoda (RIP) loved radishes and would eat them all day if we would have given them to him. Like most everything else, I would not feed a lot of radish....maybe better in very small amounts.