What is this?

[EclipseTheLionhead]

So I was cleaning under my bunny's little pan and well, there was this dark brown, sticky stuff (that smelled so bad). It was all over the walls nearby too (like it was splashed around) but nothing that I could see in the litter. What is this stuff?

 

[Apollo’s Slave]

It looks like urine to me, I could be wrong. What (and what quantities) does your rabbit eat and how old is she? And has she been eating a lot of hay?

@JBun @Blue eyes

 

[zuppa]

Can you post a pic of her pan in place? How high is it?
I suspect that your litter pan is too small or too shallow for her and she just lifts her butt too high and pee behind her pan. What you see might be urine a couple days old.

 

[Hermelin]

Dried urine, I’ve had it when my bunny Toste marks Odins cage. Clean vinegar and water, but it can have dried into the plastic so it get stuck