I have just recently had my chickens done. You need to have your chickens caught in cages because they will not wait ten minutes for you to catch them. Also depends on what state you live in, Florida makes you have a breeding pairs to get tested, if you just want to have your chickens tested just to have them tested they usually will not come out. Its a smooth process, try to have them bled weeks before a show so you can get the card back in time for a show and you can clean the blood off the wings.
I was just done yesterday!! Yeah!! Im in louisiana and the tester came out. My daughter and I took turns grabbing them out of the run and after tested i just let them free range. Very quick process but a tad messy so wear old clothes. Good luck!