Bunnie use to go into stasis alot and her poos use to be really soft on a regular basis and she'd have stodgy poo stuck to her bottom fur so we tried putting her on a high fibre pellet - Oxbow Bunny Basics T and we noticed a difference in and no more poo blow outs or messy bum.
The frequency of a bad tum and often going into stasis slowed down but still kept happening, until we tried stopping the little bit of veg she did have and that seemed to do the trick. She went over a year without stasis or messy bum so it was obviously the veg. Not all buns can stomach it if delicate tums.
I would recommend changing if they prone to tummy upsets as it helped Bunnie a lot and even stopping veg.
Just feed limited amount of pellet and tonnes of hay. Keep eye on weight if loose's a bit then up pellet a bit - we had to trial and error to increase the pellet to a right amount that wouldn't upset her tum.
She was on Selective Science when we got her but kept getting chalky wee so changed food to excel which stopped the calcified wee as excel had less calcium content and didn't contain Alfalfa but she kept getting messy bum and stomach stopping, so switched to the Oxbow and limited the pellet and no veg - and she done well.