I was at a local garden center and almost bought wheat grass seeds - the lady at the counter said they grow quickly? Was thinking of potting myself and putting in my little guys enclosure...
But sorry, don't know where to get them already sprouted (went off topic question - sorry!)
Wheat grass grows quickly AND it roots very deeply and densely. It's kinda a pain to pull out when you're through with it. Just like pulling grass. I prefer to keep mine growing elsewhere, but that's just me.
You can buy seeds on Amazon for cheap!!