Theyre made from air dry clay, it's rock hard after drying a few days. I was going to use Polymer, but the baking in the oven and all seemed a bit hazardous and i was worried about messing up and cracking them.
I have TONS of bubble wrap and other stuff to package them in. I was also considering trying styro-foam for shipping...cut out for the bird(s) to lay snugly in.
I am headed to the post office in a few minutes to check on box sizes, flat rate will probably be cheapest. I don't plan on shipping them in anything too small. I want them to get to their destination safely.