All the cute herper males on Tumblr seem to be getting this one. Maybe there’s fanfic in the offing?
I don’t know who’s been telling you that quail are bad for snakes? But thats not true nutrition-wise. Quail are perfectly reasonable feeders. Though rats will offer a more balanced nutrition content than other feeders. But mixing them up a bit is fine too.
The only reasons I can see a quail being bad for a snake is if the feeder is tainted in some way, or if the beak/claws manage to harm the inside of the snake. Though that is uncommon to happen.
Quails make exceedingly nasty results coming out the other end, but that’s no reason not to feed them. Just be aware that fish or fowl feces are usually nastier than rodent.