When working in the Pet Shop, we received birds from around the country in freight boxes similar to the image below.
birdbox.jpg
You need to make sure you have a small container secured to the inside of the box, in that container, you stuff it full of cotton wool or dacron fibre, then fill it with water, the birds can then suck the moisture out of the container without any major risk of spillage during freighting.
Seed is generally in a small container also, it usually ends up all over the floor of the box, but that's no real issue.
Make sure you're able to arrange pick up of the birds on the morning they land, and everything will be fine.
If you need to get your hand on a freight box, most bird dealerships keep a few aside out the back of their shops, so a few phone calls should be all it takes to get organised.
Hope that helps.

You do not have the required permissions to view the files attached to this post.