Hello and Merry Christmas everyone...
Has your bunny's urine went back to yellowish/normal?
Our bunny seems to be having similar issue... We noticed reddish color urine a couple days ago but she was also probably stressed/territorial as she was in another environment (an emptied bathroom). We had her litter box and some towels so she could rest/sleep on, but she preferred to do her business on them and not use her litter... Same looking spots like image in OP.
We looked up some info online as to the reasons this might happen and we've come across all kinds of info ranging from food to cancer. She gets hay and 2 cups of greens daily (1 morning/1 night) and a tiny bit of seed/roughage mix (Living World Classic) as a treat. Her greens contain romain lettuce, cilantro (which apparently gives a reddish coloration to urine), fennel, dill, mint, broccoli and parsley (little quantity and not often) an inch sized piece of carrot or small wedge of apple. We try as best as we can to give her the best diet as when we found her (yes, she's a rescue.. Some idiot thought leaving her in a park just before temps started to hit freezing!), she had a sizeable dewlap, not large enough to be problematic or worrisome but still, result of bad feeding habits the previous owner put her through.
So we also don't know her age, but I saw her because we managed to check her and she's definitely a girl...
Though the reason I'm writing all this is merely an introduction to more freaking-us-the-heck-out continuation of things.
She's been back home and in her cage almost 48 hrs now and yesterday her urine was clear and we thought that that was it, stress of not being in her comfort zone, back in her hutch etc... But this morning, we saw blood traces in her litter and even a few clots... Her demeanor hasn't changed, she still pretty calm, affectionate, cuddly... Eating normally, her greens and hay also active, we let her out of her cage often to run about (supervised, of course)
She has the habit to "hump" which we figured is due to her not being spayed and just before I went back online and found this post, she had done it again as my gf was trying to pet her but she "sprayed" a little blood jet (sometimes liquid would come out)
We're quite stressed with this (though Lapina doesn't seem affected one bit!) specially if this is an urgent situation as we've found it very difficult to find a vet who knows rabbits even more so this time of year when everyone's off...
Your insights and suggestions are highly appreciated