Welcome to the forum. Might I make a couple of suggestions knowing what little I do about your place. Cow are some times the best thing to have for a good quail environment. Seldom do they eat anything down to the ground. Judging from what you've described about the vegetation seems like there hasn't been sufficient rain fall to maintain the habitat which is nearly the whole piece of pie when it come to a fragile quails survival. It takes certain grasses and seeds that they produce for nutrition. If you don't have some of these plants and you want to have "wild quail, you might need to talk to an ag person for advice.

I also might caution you in releasing pen raised quail as they will destroy and breed with what wild quail you have and by that I mean their habits will change and they won't respond like a wild bird! I don't pretend to know everything about quail and you could learn a lot more from others also. It has been our main source of hunting up until the last three years as we have lost our habitat, hence the quail go with it. Get plenty of info before you do anything. My2cents