Penny, it is great if you have the space to keep new or returning birds apart from the flock for a few weeks. It's not always possible as you suggest. But it works great if you have some individual coops where you condition in a seperate area. You can return them there for a time just to be careful. Whatever you can do with your set up is helpful. In any event, try to care for the main flock first then take care of the returning birds. Afterwards clean up utensils, clothes and shoes before returning to the main flock. You can also take some effort to give them some supplements or vitamins while they are getting to spend time alone. I wouldn't suggest any antibiotics. But give them some extra treats and watch them for the time you have them apart. To be extra careful you can bring in a few from the main flock after a time in the quarantine area. Give them a few days to see if either group has any reactions. It's not fool proof and of course everyone has their limits in space and time. Good Luck and enjoy your show time with the birds and fellow breeders.