To keep 20-30 quail for dog training purposes I would recommend a Johnny house. You would be able to release birds for training, then let them come back on their own through the recall cone. Here are some pics of the first one I built:
An electronic recall system might be beneficial to you...here is a link that may help you out.
http://www.qualitywildlife.com/They have the recall systems, and it's where I bought the less mess feed and watering system I have in the pics. I built a waterer and feeder out of PVC using those as a model...they work OK but not like the ones I purchased. Those are in my second J-house...problem is I have no birds in either of them right now!