My goldens are actually tame enough I can usually just grab them. I usually net the ringneck pheasants. I have used a recovery cage like you're talking about for quail - you put one bird in the cage and it calls to the others and lures them in. Not sure how well it would work with goldens. I have also set a large cage in the pen and sprinkled scratch grain inside then closed the door once they went after the scratch.