The field trial grounds are only a small percentage of the land out there. I was out there this morning also, but stayed away from the area they release the birds. Dropped the only rooster I had a shot at but he must of hit the ground running, never did find it..
Those releases kind of suck IMO, before season I find plenty of wild birds while running my dog then they dump a bunch dumb birds there and a hundreds of people show up and blast everything around. Next week there won't be but maybe one or two groups hunting that entire area compared to the dozens of trucks today. Luckily I've found a few other areas that have some birds.