There was a talk on rabbit feet including pododermatitis at the RWAF conference. They said that the research shows that house rabbits are far more susceptible because surfaces like carpet are much more abrasive (the same is true of vetbed, which while great for many sick rabbits is not good for those with sore hocks). From the research, the only surface with a significant reduction in sore hocks incidence was bedding on thick hay. So after the heatwave, moving them outdoors onto a surface spread with lots of hay is probably going to be helpful. I have a feeling FHB used to fashion something a bit like a giant corn plaster out of a piece of pipe insulation for some rabbits with sore hocks, to take the pressure off the worst part!