Yep pretty sure they are bored, I usually let them go out for a bit on Mount Poopmore, but with all the snow and now it's in hip deep drifts, I am trying to clear paths to everything.Maybe your gang have cabin fever from not being able to get outside. It sounds like you have lots of space with a whole barn, but I have found that the more space the better for those inevitable Canadian winter weather days.
I had a good chuckle when they ran outside only to be met with piles of snow preventing them from getting any further than the front door - that's when Pangoo decided I was fair game! The brat!
I tried veggies but they just ignore their carrots etc which freeze and then they won't even look at them. So I make interesting piles with the hay, spend time entertaining them... That could also be why they were bonkers - I wasn't there to be their entertainment and peacekeeper all day! I get my network fixed out there it's business as usual and I can once again keep any eye on them while I work, it's a wonder I get anything done when I am working from home!!! I could work for me forever