I dont have screening on it at the moment; I just have a couple pieces of light diffuser that I got from work, and thats mostly to keep the dog from drinking out of it. It is under my patio so Im not worried about birds flying over and seeing. As they grow and get more noticeable Im going to get some netting and attach it (with clips or something) over it to both keep things out and keep them in.
I cannot get over the size difference!! That biggest green one is over an inch now and I still have some teeny ones, too. Their colors are already brighter in just the short time they've been out.