I have ND who are eating a lot of oak leaves/branches of trees we have recently cut down. I noticed that since they have been eating these leaves (both green and.brown leaves) that when I bring them out of the.barn the next morning their urine is orangy/burnt orange color in the shavings). Is this normal? Should I just keep them in their small pasture area away from all of this until I can clear it all. Just want to make sure I'm not harming them by letting them graze on all that. They are eating and drinking like normal and have tons of energy.