Hansa- of course, the truth is, no one knows. Certainly, any flocks- even the biggest commercial flocks- which show any signs of actual disease will be culled immediately.
The wild card is going to be what TPTB will do about smaller flocks, or flocks which show no signs of illness, but after all, are still chickens.
I fear the "we're all gonna dieeeeeee!" mentality will prevail, which will mean that they will rapidly make keeping ANY small poultry flocks illegal, and you'll see all sorts of well intentioned- but poorly designed- regulations about chicken crossing state lines (or even county lines, given a pandemic situation).
So, I do think it's probably a wise prep to stock up on chicken and turkey now, if you have the money and freezer space. There is an interesting question in my mind about whether chicken will be extremely expensive- due to all the culls and a lack of supply- or dirt cheap, due to people's fears about "catching" the flu from handling chicken or eating it.
Doesn't matter to me.. .I'm growing my second batch of 50 Cornish Cross meat birds, and have Thanksgiving and Christmas dinner on the hoof as well, gobbling their heads off and growing like weeds.
I'm hoping it doesn't come down to a forced cull... I've got some fairly rare breeds out there in my laying hen pen, and I suspect that my birds- because they tend to free range and also end up sharing feeders with wild birds- probably have at least some immunity. Bird "flu" in one strain or another is already pandemic all over the world. Birds which were raised in complete isolation, with all sorts of biosecurity measures keeping them from ANY germs- those are the ones which will be at real risk.
For those thinking of stocking the freezer, just remember to use heavy freezer bags, and draw all the air possible out of the bag, allowing the plastic to "hug" the meat.. and you'll have very little freezer burn. For long term storage (a year, or even 2, if you are really careful) you have to use a freezer which does NOT "self defrost" and you want it set down at 0° F, or even a little below that. We've eaten 3 year old chicken from our freezers under those conditions, and there was no way to tell how old it was by the taste or texture.
Summerthyme