Shnook gets fed a little over two cups of beatpulp and four cups of Purina Integrity (Fat and fiber) twice a day and Trevor gets fed two cups of beatpulp and one cup of Purina Integrity twice a day. They have good quality free choice hay, they have more of a barrel/huge bucket for a water trough but it's always filled and has a de-icer in it. The water has a lot of sulfur/iron in it, however, this is the first I've seen a urine spot that dark.. They have a big salt lick block for when they're outside and for the odd time they go in their stall they have a smaller salt block on the wall of the stall (They only go in when the weathers really harsh.). I know darker urine isn't that uncommon to see, but it was more of the red-ish hint to it that has me a bit worried.
Anyways, here's a pic so you have more of an idea what I'm going off of.
Any input would be greatly appreciated.