I don't offer it because im pretty sure they wouldnt touch it. You can always try. I havent even seen mine eat grass when they live outside during the summer.
mostly tortoises like sulcatas and leopards will eat hay. and usually only the adults. i doubt a Herrman tort would eat it, they like mainly broad green leafy weeds and plants, but it's always nice to offer! i personally offer sweet meadow and dried Bermuda grass!
My sulcata was always eating the substrate along with his food (dragged it off of his large eating board). So I surrounded the area with that stuff, now he eats a mouthful of hay on accident instead.
I feed my one year old sulcatas timothy hay with the mazuri. I cut the hay into tiny strands and when I wet it with the muzuri, the hay softens. My sulcatas just love it. Hermann torts may be a bit more picky, though.
When I first started keeping tortoises, I used ZuPreem Timothy as my ONLY hay source...that's feeding and bedding. Now, I use it strictly as bedding for the 3 year olds...but ONLY use 'real' hay for the Sudans...and then I only use orchard grass and alfalfa. Check out my bottom two links in my signature...the lasagna and meatballs can be made with any hay...so it's easy to get rid of that unwanted timothy!
I don't use Timothy, but orchard grass hay and Bermuda hay are staples of my adult sulcatas diets. I don't think most other tortoises are just going to walk up and start munching on dry hay. If you blend it and mix it with greens, they might eat some of it.
I give my leopard Timothy hay over the heat mat area that I change regularly and it sleeps there (it loves to sleep in hay and won't wander at night), but I've only seen it eating a piece once. It was a big bud or whatever (where the seeds are formed).
What I do now is chop some up with a pair of scissors, sprinkle it over the greens, and spray it. Then I put a couple pieces of Mazuri on top of the hay and sprinkle a little more. I don't see any left in the dish at the end of the day so apparently it's being eaten. I filled up a plastic container with finely chopped t. hay so it's not very time consuming every morning.
I think you specifically asked about the hay the pet stores sell for rabbits and guinea pigs. No. In my opinion that stuff is too old and dry for any self-respecting tortoise to bother with. If you want to feed hay (and if you have a Hermann's then stinax gave you good advice), go to a feed store and ask the proprietor if you can purchase and scoop up some of their grass hay "leavings" into a bag. It is softer and fresher and not so pokey. I buy a bale of either orchard grass or sweet meadow grass hay from the feed store and keep it in my garage, covered with a tarp. I will put a "flake" (a flake is about 3 or 4" where the hay breaks apart naturally) in with the Aldabrans and with Dudley, the sulcata. They eat it or they don't, depending upon the mood they're in that day.
I've used all of the types of hay we carry in the store with mixed success. Generally, it seems like forest tortoises and babies are unlikely to touch the hay much, but grassland species that are 2 to 3" or larger will readily eat it if they are not overfed with fresh greens. For example, they won't touch it the day we feed fresh greens - but since we only offer fresh food 3 to 4 times a week, and pelleted diets the rest of the week, on days they don't get fresh food they'll quite readily eat the stuff. Timothy, bermuda, botanical mix - we carry 6 or 7 kinds of hay and they tend to eat it all I also occasionally bring the loose hay from the bales that my mom gets for her horses, and all the tortoises will happily eat that. Freshness of the hay does have a direct effect on how readily they'll eat it, at least that I've seen.
Since in most households, the family tortoise is fed a nice rich diet of fresh greens, they are rarely hungry enough to want to eat something dried out and less delicious like hay. At least among customers I encounter in the store, this is typically the case.