[riverdroid]

Seems like it could go both ways, couldn't it?

Free ranging birds are in less proximity and healthier conditions. There is less contact between them, more sanitary conditions, and healthier birds. But yes, they could have more contact with outside pathogens.

Whereas many poultry barns have thousands of chickens standing in their own excrement, shoulder to shoulder. There are even decaying corpses strewn about and being pecked. Whatever pathogens in there with them could spread and mutate readily, and the birds are likely less healthy and more vulnerable to it.

I'm not sure if there is solid evidence to claim one is more risky than the other, but I think it would be the former.