Welcome.
I'm not sure that Russians require hay at all.
But I DO use hay as bedding for my outdoors Redfooted tortoises. They also don't eat it.
Are you keeping two Russians together?
Two Russians can not live together, specially in a small table. A 4x8 is minimum for one Russian. Russians and most other torts do not do good in pairs. One will bully the other to sickness or death. If they are hatchlings, you might get away with them being together for a short time. Use dirt or coconut coir or peat moss for a substrate. I use peat moss now and in the fall I add leaf litter