Substitute for Hay

I know everyone here read the title and is currently typing "THERE IS NO SUBSTITUTE FOR HAY!" or something like that. In my case I live in a third world country as an expat and got a bunny today from a market. I expected the store to have hay, but they did not. And before you suggest leaving the poor bunny there, know that she was out in the direct sun in 90 ish degree weather with only pellets and a water bottle in a tiny wire bottom cage with a sickly bunny. Luckily I must have gotten her pretty early as she seems to be fairly healthy other than mild sore hocks. When I got home I gave her cilantro and romaine lettuce, as well as some rabbit pellets that claims to have high fiber (and a water bowl). She is eating well so I know that she's OK for now, but I might not be able to find hay for a while. Are there any vegetable that can (for now) be a substitute for hay? Should I just feed grass? Thanks in advance!

Grass is the best substitute for hay. In the end, hay is only dried grass and in the wild, rabbits mainly eat grass. Grass is perfect to wear the teeth and it has the correct amount of fibers for the digestive system. It also bring very few calories. Hay is prefered because it has a lot of variety in it, which is hard to recreate when you go plucking grass yourself. It also has a bad rep with many owners because considering it just comes from outside it can be soiled with other animals' urine and bring illesses. On the other hand rabbits tend to eat it better than hay as it is more appetent and it brings extra hydratation which is great. So grass is a good substitute but you will have to give a lot of it (like hay, the rabbit will need to eat at least his body mass in grass and he needs to have some available constantly - it happened to me to have to give grass instead of hay for a few days because I just arrived some place where hay wasn't available and I felt like I was spending my days managing grass) and be sure to wash it before giving it to make sure there is no insect / urine on it.

what Aki said. Grass.