pee discoloration

Hello so my friend sent me a photo he has 2 girls as well and wanted me to ask he feeds them oxbow food and treats and veggies like Lettuce and carrots and he has pee pads under their fleece blankets and noticed an orange spot but it doesn't look like blood and they aren't bleeding or anything

photo Hi, i have a guinea pig around 11 mo to a year, she’s starting having a weird discoloration in her pee and poop. She does her business in the same corner so it’s hard to tell. I just started giving her cilantro but don’t think that’s the case. Can anyone help? I’m concerned and it’s late...