I'm forgetting what exactly the reasoning was, but I looked this up at one point and apparently there's a difference between the chickens used for laying eggs and the chickens used for meat. It's not that one is resistant to the virus or anything, but apparently we aren't concerned about the stock for meat. It won't be affected as much as eggs.
Prices haven't changed for meat by me. $3.99/lb for the cheap supermarket "brand" as it always has been.
Edit: I looked it up and actually the chickens used for meat, broilers, are apparently more resistant to the virus but also live MUCH shorter lives. They were bread to bulk up quickly to go to slaughter as fast as possible while chickens used for eggs take more time to get to egg laying age and are more likely to get the flu and die.