That's entirely possible. Bio-security is essential.
Our large 700 member chicken meetup group occasionally has coop tours and our gardening group has an annual garden tour. If I'm on the tour, I make everyone wear disposable booties when they come on the property and don't actually get access into chicken pens. I'm still taking a gamble doing that and I probably won't be open for tours in the future. It just isn't worth it.
Other members have boot washes at their gates and make everyone disinfect their shoes before access.
If one brings in new birds they should be quarantined as far from their flock as possible and for as long as possible. Preferably for a month or more. During that time, tend your birds prior to tending new birds and wash up and change clothes and shoes between.
Our large 700 member chicken meetup group occasionally has coop tours and our gardening group has an annual garden tour. If I'm on the tour, I make everyone wear disposable booties when they come on the property and don't actually get access into chicken pens. I'm still taking a gamble doing that and I probably won't be open for tours in the future. It just isn't worth it.
Other members have boot washes at their gates and make everyone disinfect their shoes before access.
If one brings in new birds they should be quarantined as far from their flock as possible and for as long as possible. Preferably for a month or more. During that time, tend your birds prior to tending new birds and wash up and change clothes and shoes between.