I tried to find a local vet to see if I could purchase some liquid calcium, but the only vet I could find that had any experience with birds had little to offer. She had experience with large hook bills, but none with finches. She didn't have any liquid calcium. I will purchase some today.
I found the sticky here on treatment of egg-binding, and did what it said. After two days, the hen was able to pass the egg!



This is one of the reasons I am VERY glad to have found this forum. The hen would probably have died otherwise.
Mike