yellow urine

so buttercup isn't as well as the vet told me she is. Her urine is bright yellow! I have a vet appointment for tomorrow which I'm praying I can get to on time since its cutting it close to when my partner finishes work and he needs to drop me. Wondering if anyone knows what it could be though...

I'm getting very worried about the appearance of their urine. It's yellow. I read that is suppose to be clear but I don't remember it ever not been this color. They are 6wks and 4days old(estimate). Kiku could be older. Like I've said in other post they have seed mix Kaytee fiesta and pellet...