Good news! Rounder and Susie both swam at the same time today, not freaking each other out as they did yesterday. I took Rounder down to their cage today when it was so hot in the rest of the yard, and when there was shade down there, and instead of closing her up as I had been, I left the door open. She is always more content there, since she knows her food in on one side of the door and water on the other. Susie crept down there as soon as I left, and soon, both of them were sitting contentedly in the shade of their house. I did find niacin today and started adding it to their drinking water. Still haven't done anything else about Susie's Angel Wing. I really want to get her a bit more accustomed to her new home before traumatizing her any more.