I guess she knows that hay is good for her. I've never had a bun who refused herbs and other 'treats' but continued to nom hay. It must make it really difficult to keep her weight up. Your buns don't make your life easy for you, do they Jane? They are very, very lucky to have a carer who has the time, patience, knowledge and an amazing vet to look after them so incredibly well.
Sending more vibes for Eliza xxx