Yes, I do splice the feathers myself. I have a small custom arrow shop.

There are a couple of ways to do it. You can either just cut the quills and "zip" the feathers together, then place them in the fletching clamp for gluing, or you can actually cut the feathers from the quills without cutting all the way through the quill, and glue the new feathers to the empty spot in the quill. Both ways are quite tedious though.