@BoboFarm Could you provide the link? Most of the examples with vinyl flooring I have seen were for mature pets, not breeders with kits, and in large areas I have seen they are usually provided grass mats or the like for traction.
Depending upon the grade of vinyl, it has some cushion and can be impressed. Rabbits nails can give them some traction on vinyl. Even so, my second rabbit was an litter box trained, indoor pet. He slipped on vinyl that was non-slip type one morning and lost the use of his back legs and control of his bowels, stopped eating, and died within a week. The vet, which was a vet for small and large farm animals also, told me it was not uncommon, which is why he strongly was not in favor of rabbits being raised on hard or smooth floors of any kind.
The two kindles with some developing splayed legs were on a material similar that was piled high with straw in the nesting side of our brood cage, which was my husband's idea. The kits, of course, moved the straw around until they were on the bottom. They did not have the necessary traction to develop correctly. Some did better than others but a significant number had at least two splayed legs.
Concrete is not the same as vinyl and vinyl is risky enough. While some people think that wires are not good, I do not have rabbits with sores on their paws. We do provide our rabbits with warming pads, which are turned off on warm days. These pads allow them to be off the wires if they desire to be, but they rarely are on them except in the winter. The wire flooring is really not as bad for rabbits as people make it out to be.