The problem with quail is that the most useful, the Bobwhite, is not an indigenous bird and any form of releasing is prohibited. Those people who do use them do so on the basis that they are only releasing tham on a temporary basis and that they will return to their Johnny House.
Pigeons can be released but only homing pigeons as you are prevented from catching up ferral pigeons and re-releasing them.

I have a small loft that currently holds four birds and I have two releasers a manual one and a remote activation one.
The blue oil drom is a mobile Johnny House that I used for Bobwhite Quail. The Bobwhite weren't very hardy and tended to die off in the cold in February. The courtnix quail were much hardier and were used in the pheasant release pen. You could walk into the pen and flush them out into the field but you would have to move about in the pen to stop them comming straight back in. Once flushed in the field they went straight back into the pen. We made a point of not driving them out more than once a day. They were also "thrown" into light cover and picked up by hand when the dog had pointed. Some were kept unfit so they could be used in this way.