British Columbians are known to fly whole fresh salmon to Alberta and Ontario. The process is ad hoc and quintessentially Canadian as follows:
- catch a beaut in the morning (or get a fresh one from a buddy who's out in the chuck that morning)
- put the fish on ice as soon as it's caught
- gut the fish
- wrap the fish in a plastic bag, seal with duct tape
- wrap that in an old plaid jacket
- wrap that in another plastic bag, seal with duct tape
- put that in your checked baggage
- drive to the big smoke
- get on a plane
- barbeque the fish for dinner
The key here is to get and keep the fish good and cold prior to insulating it with your plaid jacket. Once it's inside your suitcase it'll be pretty well insulated from warming up. I figure you've got about 10 hours of transport time before it's warmed up so much you need to cook it. Flight time does not count toward that 10 hours -- the luggage compartment is pretty cold.
There's no border between BC and Ontario so, in this case, there's nothing to declare. However, I'm fairly certain that there are restrictions against bringing fresh food into the USA. You should probably figure out whether you're allowed to bring your sausages across the USA border.