Hi Bertie is right, the way to try and solve this is perhaps to cut out dried food completely for a while, until the rabbit is happily munching the hay.
Once hay is back on the menu then gradually reintroduce a small handful of dried food, but more as a treat and not as a main staple.
Adult bunnies can quite happily live off hay and a few veggies, and no dried food at all.
Our Sanctuary bunnies, many of whom arrived with exactly the type of problem you described were initially put onto a hay only diet until they had to eat it (as they will opt for the dried food as a staple if allowed to do so)....once they were happily eating hay, then they were given a dessertspoon of dried food once a day, but no more.
With 26 rabbits here, and many having been cured of the sticky bot syndrome, we have found the hay is the key to all round good bunny health.
Bunnies diets need to be kept simple and although a handful of herbs and a few veggies make a nice treat, it is the hay which should be their main food, far too much importance is placed upon the dried food.
Our bunnies are full of vitality and healthy despite the majority of them being aged 5 years plus, we have tried every diet in the book, but the one that works is hay! hay! and more hay!.
If given the option bunnies will eat predominantly dried food, and this is why they end up with gut problems and sticky droppings.
It is the constant munching of hay that keeps the gut healthy and things moving, and reduces the risk of teeth problems.
Bunnies will eventually eat the hay if left with no other alternative, and once they get the taste for it, they tend to relish it...our bunnies now prefer hay to the dried food, which is quite a turn about!! :lol: .