What makes you think it's a hybrid?
What species is it, where do you live? Very different answers between Europe and the US.
A european rabbit, domestic or not, that young would have been exceptional lucky to survive from that age anyway, let alone out of the nest after being dragged out of it by something, quite likely with teeth and claws. But mixis between wild and domestics happen, they are not hybrids but the same species. I once had such a litter when a small wild buck squeezed through the fence and knocked up one of my does.
Cottontails are born way more developed, better chance for survival. Although despite different chromosome numbers etc. hybrids able to survive are theoretically possible, can't be ruled out completly (I guess depending on which cottentail spieces is involved), but rathervery unlikely. Then surviving ending up on the sidewalk, and being found would be like winning the lottery 3 times in a row.
Normal cottontails end up somewhere quite often, it seems to me, no wonder, they are more developed, and the nests on the surface.