Seems like everyone is encouraging you to take your birds with you. And I'm picturing days of yore when people would strap everything they owned onto the ol' pickup truck with the cages of chickens on top, and off they'd go, California or Bust.. . But nowadays everything goes inside the SUV and people and animals are stuck inside together, for better or worse, for the duration... I drive a couple of hens to my Mennonite lady for her to butcher and process for me from time to time. She lives four miles away from me, it takes about ten minutes to get there. I usually take two to four chickens at a time. But let me tell you, two minutes into the drive we're rolling the windows down and hanging our heads out. I can't imagine traveling 15 HOURS with chickens in the car. I'm not here to advise you what to do, but I strongly suggest you put a few chickens in a crate in the car with you some morning and just drive around town for an hour or two as an experiment before you make up your mind this is what you really want to do.
) the key would be having fully prepared housing at your destination, i.e. coop or run or secure location, with room to initially place all your carriers into so chickens can settle themselves.
