With a little bit of food, I was able to get them all in, but it was tight for floor space, so a few of them flew over the 4' wall when they were done eating - but couldn't escape the closed barn doors. Partial success.
The big improvements that first time (technically 2nd) were having a folding plastic table on the other side of the barn doors and a trash can. Things went mostly smoothly.
The third time., I set up the table and trash can the same, but led them all into the grow out run (walls 6' high, much more floor sapace. It worksed m,uch better. I plan to repeat that, 4th time around - early October, I think.
and SourRoses, its a bit of streess leading in (what if they test positive?), but its free in FL and real peace of mind afterwards. I recommend, even if its NOT a guarantee of a disease free flock, at least you know you are free of a couple very serious diseases on the day of testing.