Im just starting to get into dorkings, so i don't know a whole lot. I believe the 5 toes thing has very little to do with leg/foot problems though.... I think.
Ok, I had to go look it up. Extra toe casuing leg problems, not so much aside from ingrown toenail or getting caught. Dorkings though... apparently their extra short legs and hips make hip problems more common, and the low barge shape with more weight adding to the short legs means jumping is hard on them, so low roosts and nesting boxes, 2 ft preferably. This is good to know since I'm about to redo our coop for a bunch of dorking chicks...
My Dorking crosses have short legs, but they roost in the rafters with everyone else. No foot or leg problems with the adult birds. They're a multi-generational Dorking-Sussex cross.
Most of my birds are big. I attribute their comfort with high roosting to being put up there as chicks so they had the chance to "impact train" their muscles and bones. (Not well edited--they start coming down at about minute 7)
Good to know that they're prone to these issues. Do you have references I can look up? It sounds like these issues tend to affect adults more than chicks?