Thinking about getting some quail; any advice?

I'm not exactly new to keeping poultry; I have eight chickens right now whom are all doing just lovely. But I'm not sure exactly how different quail are from chickens in terms of space needed, if they get broody or not, how much they eat, etc.

I do already have a pen in mind for about three quail that's about 2x3x2.5 feet, and has a smaller one square foot outcrop. I was going to have the whole thing up on stilts with a mesh bottom, but would it be better to just have the thing be out on grass or dirt? And while I've heard that quail do fine with about one square foot per bird that just seems a little... small.

I was also planning on keeping the quail relatively close to the chicken pen, so does anyone know if there are any diseases that can hop between them? And would it be possible to do a mix of chicken feed with regular quail feed, or to just keep them completely on chicken feed if I supplement their protein with something else? The stores around here only stock quail starter for some reason, and thats around 30% protein, and I'm pretty sure that adults only need something in the 20% range.