I knew about the avian flu via the Indiana thread, but heard nothing from state of Illinois. I even have a premise ID # for my flock. Nope, no one contacted me.
Around 2013 or 2014 there was a big avian influenza scare because many large commercial flocks had to be euthanized. It was later discovered that most cases were spread not by migrating wild waterfowl down the Mississippi flyway as we were told, but by humans. The equipment, trucks, employees, and deliveries would travel between locations and carry dust/danger/etc. with them. Because it spreads so quickly & easily, every bird on the property must be killed to prevent further outbreak. AI could seriously wipe out a good portion of our country's food supply, so swift hard action is required.
Sure I read that some backyard flocks got it, but it was strange that people who had free range chickens (no containment from wild birds) were not affected as much as the commercial farms whose poultry never went outside to see natural sunlight.
Increasing biosecurity at times like this is still recommended. In addition to quarantining new chickens..... Save a pair of old shoes, coat, gloves, etc. by the back door. Only wear it in your yard and not around town doing errands. You could accidently pick up more than a bag of feed from the store or visit a playground with frequented by wild geese and bring an illness back on your clothes/shoes. If visiting someone with chickens, a county fair, petting zoo, etc wear different clothes because the increased exposure risk. I kept some disinfectant spray for guests' shoes ..... or an extra pair of crocs for a visiting kid. (Keeps their kids' shoes clean anyway.)
My flock is inside the coop for the winter, but at some point they will go outside. I try to make my yard less appealing for wildlife. The chicken feed is in a treadle feeder in the interior run and I only put out enough fresh treats to last about 10 min. That way the wild birds don't take it. During chick sales, I set up a chicken tractor in the front part of the backyard. Visitors don't enter the back where my chickens live. The broody hen and her chicks are exposed, but quarantined to the garage.
I admit, I get lax sometimes about my own rules, but the thought of losing all my chickens scares me. It's bad enough when I lose one to a hawk.