Lizzy has, in the past, gotten poopy-butt when the only change to her diet was a different kind of hay… I don’t think I’ve actually seen anything that says this can happen, but she’s been on the same kind of hay for months, and no poopy-butt. It could just be a matter of adjustment. Like anything else you feed them, probably a good idea to start out with limited amounts of the new edible, and work up so their system can adjust…

Alfalfa hay can be too rich for older bunnies (high protein) and can cause excess cecal production. This could be what you’re seeing.  Have you tried the other softer cuts of grass hays, more fragrant types?  I’ve read of Fuzzys troubles in your other threads.  I read about pellets that are 100% hay recently.  Here’s the link to a discussion about them: https://www.binkybunny.com/FORUM/tabid/54/forumid/1/postid/82506/view/topic/Default.aspx

This may be a short term option to increase fiber in his diet.  Then hopefully he’ll eat hay again after a molar reduction (???) Hopefully!!!

I would try to mix it with other type of hay he is used to.  But with Fuzzy’s medical problems it may not be only the change in hay that is causing some mushy stool.  If he is not eating like a normal bunny and needs to be force fed, etc- things are not progressing thru his gut like a typical bun that snacks all day.  If he is eating the alfalfa that is great- and it is a good sign that he will accept other types of soft hay.

Since your vet specializes in rabbits I would ask your vet about the alfalfa and what recommendations are- obviously any hay/fiber you can get Fuzzy to eat willing is a huge plus!  But since your vet has seen Fuzzy recently and knows what his body condition is like (weight, how skinny, how easily to feel spine and ribs) your vet would be a great resource in clarifying that an alfalfa diet would be approp.  It may be that Fuzzy needs a richer diet that he WILL eat and manage any symptoms of that in other ways.