>>how many russians can an outdoor 5x5ft enclosure support?

I had an 8x8 outdoor pen and found that 1 male, 2 females, and one juvenile were OK. Until the juvenile matured into a male and had to be separated.

With 5x5 I would just go for one pair of animals. Especially if they are wild caught. They once roamed the plains of Central Asia - 25 sq ft will be hard to adapt to.

I have two captive bred (from my wild caught stock) russians that I will place into a 4x4 pen next year. They've spent their entire lives indoors in enclosures no larger than 7 sq ft (with short stays outside in a mesh enclosure) and don't claw at the corners like wild caught specimens do. I will also try to create as interesting an environment as I can. Things to crawl under and over, basking and shade, rocks and plants, etc.