I just ran across this article that explains why meat chickens have not been affected much by the bird flu. In a nutshell, their short lifespan makes them less vulnerable to the flu because they are not around for long. I hope this link works.
Broiler Chickens Bird Flu
I mentioned before, I watch a youtube channel from an animal farmer, it's a small family farm, he just raises chickens, eggs, pigs, a small breed of cattle and turkeys for Thanksgiving and sells direct to consumers in a large farmers market. He pasture raises the animals as much as possible (not during winter). He has mobile chicken coops that he moves about the pasture, I think every week or two. The chickens spend the night in the coop but when he opens the door in the morning they rush out of there as fast as possible. They'll stay outside until sunset and then go back in the coop. I think the large commercial egg operations may provide outdoor access to their hens but they might have to explore a bit to find the access door, so most of them just stay put.
