Bringing them to the fair is a great idea. I would not give them away though. If someone is willing to pay an adoption fee, they're more than likely to take them to a vet, and take better care of them, rather than something easily gotten, easily disposed of. Not intended to insult anyone. Just my personal experience with being a rescuer for years.
Also I would not ship them without a properly insulated box. It protects them from being crushed by a heavier box, and it get's about 20 degrees in the sky anytime of the year. The insulation will contain the temps a little longer.