I don't have Russians, but for my Red Footeds, I have a few flat cement pads that I have laying out in my pens that seem to do the job. Same thing for my dog. He walks down the garden path to do his business. Cement and clay bricks.
thanks for replying , i'll just leave them alone then if its normal. he has a few stones and things to climb and walk on that seem keep his front ones down and all his digging about helps. i'll just keep an eye on them and trim them if needs be.