With them both having sore hocks (and not being Rexes), it does lean into environmental/care factors that may be contributing it. Can you link a picture of your set-up perhaps?
Outside environmental, other factors contributing to sore hocks include being overweight (I mention because weight standards by breed are arbitrary, so there is always a chance 3lb is overweight for your particular dwarf buns; a vet exam will better confirm if that’s a healthy weight), lack of exercise/movement, and unkempt nail length. You can read more information here: https://wabbitwiki.com/wiki/Sore_hocks
Also, is it actually expressing as sore hocks, or is there a chance these are natural calluses that are, at times, a bit more red? Photos may help!
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.