From everything that I've been able to find, quail are actually BETTER than rats. They have higher protein, lower fat and higher calcium than rats. They also cannot damage your snakes like a rat can. Their production rate is also WAY above rats. From what I know of the two species, quail seem to be such a better choice. Yes, you won't find button quail in the wild in Africa, but I hate that excuse. People and animals eat foods that are from across the world that they wouldn't have eaten in a natural and unmanipulated world, and they don't suffer from it.
I know that some monitors are actually recommended to be fed quail, but I just wanted to be 100% sure that I wouldn't be hurting the snakes by giving them quail. A lot of people claim that balls ONLY eat ASF rats in the wild, and so we should only feed them rats in captivity, but, well, nobody knows for sure what all a wild snake will eat. I hate when people flame others and basically assume that you're a terrible owner because in their opinion, you should do this or that.