To avoid sore hocks, raise Satins.
The odd rabbit we've seen have trouble with sores often appeared related to wetness in the cage, as observed by
@MuddyFarms. When fur builds up in a corner where the rabbits urinate, it creates a wet spot that seems to aggravate their feet. Satin fur is so silky that it rarely builds up on the edges or corners of cages even during molt, so we do not encounter the problem often.
We've raised Satins for almost 20 years, Mini Rex for around 10 years, and Polish, Rex, Cals, and NZs for spans of 5-8 years each. I have only had one Satin get sore hocks in all that time, and rarely had rabbits with sore hocks in the other breeds. I know some lines of Rex have problems, but ours did not have any particular tendency. The two Rex breeders I know locally do not have much trouble either, but they both cull hard for health problems. It may be, too, that living where we do (Alaska) encourages selection for heavier-furred rabbits in general.
Our cage floors are 1/2" x 1" galvanized wire. Most of the time, rabbits have a wooden resting board to sit on if they choose, but interestingly enough, the larger breeds mostly just eat it; it's the smaller breeds (Mini Rex and Polish) that sit on it.
Also note that there is a difference between callouses and sore hocks. Our Mini Rex almost always developed callouses on their hind feet as adults, but they were not sore. The only time it became a problem was when a particularly agitated buck stomped constantly, which began to tear his feet up and he ended up bleeding a little. Moving him away from the source of his agitation - another buck - solved the problem.