I haven't read all of the posts here, so this may have been mentioned. If you have tried different types of hay and it isn't working please consider taking your bun to your vet to check the teeth (spurs can make it difficult to chew hay while they'll still eat other softer veg and pellets - until the tooth causes too much pain to eat at all.) My bun stopped eating hay. We discovered she had a spur that had been cutting into her tongue - vet filed it down. She started eating hay again for a few months and then stopped again, but will eat pellets and some veg. It's been 3 weeks without hay - and yes, this can cause a lot of problems but hasn't yet in my bun. I'm feeding her Sherwood Pet Health, a higher density hay pellet that claims it's for "optimum health" and for bunnies who don't eat a lot of hay. Because she's avoiding hay and with a weepy eye, I took her back to the vet and was told her eye is "bulging a bit" and '"It may be a slow growing tumor" causing her pain when she eats harder roughage like hay (teeth are fine). This is my case and doesn't mean it's the same for you. That said, if you've tried the good suggestions listed in a few of these posts, please consult your exotic vet, who might be able to get to the heart of it. It might be a simple overgrown tooth causing enough pain to make your bun avoid hay - easily rectified but with some expense. I'm giving my bun more of the Sherwood pellets to help supplement the loss of hay. This isn't the ideal diet, of course. Hay is a staple requirement. But in a case like ours, where we have resolved tooth issues and are likely looking at something more serious, we are seeking to provide comfort over a stressful and invasive surgery for this 5 year old mini lop. Best wishes.