Birds in an envelope postcard, any size, swap

Just having a sort out of my postcards and I have some good looking birds here just waiting for some new owners. The feathered kind of birds that is - kiwis, penguins (and a couple of misplaced sheep I don't know what to do with). They are the larger style, about 8 x 4 inches. So........

Do you have a similar problem if so.....

put 3 of them in an envelope and and post to one partner. Any size of postcard is fine, so if you are a fan of just the regular postcard size don't join. The cards should be unwritten and new, or unused from your collection as long as they are in good order.

Newbies welcome.