I’m new to rabbits and these are my first 2 little girls, I’d say they’re about 3 months and so.
Yesterday I cleaned up the rabbit room and made more room for them to run around and play, since we have ratter dogs and I’m pretty sure it’s impossible to keep them safe outside of their own room; I used a bag of dog food to block them from going behind some furniture and it seemed to work and they didn’t care for it. Well this morning when I check on them I come to see that Maggie was out of her cage and had chewed a hole through the bag and eating kibble. I can’t say for sure how long she was out or how much she’s eaten but since then she’s acting different, my other rabbit that shares the cage seems perfectly fine otherwise, she was in the cage.
When letting them out Clementine was the same as always, but Maggie wasn’t too interested in going out and was just laying in her cage, she then decided to come out but was hiding in her box tunnels rather than being her normal bunzilla self. They both still eat their pellets but not with as much interest, and in their litter box their poop is about half the usual size and hard.
I know different behavior is bad in rabbits but it’s still not at the point where it seems like an emergency, lately they’ve been having a lot of cecals too on top of that, not so much today after eating dog food. 
Should I just keep a close eye on them for now? If so what other behaviors should I be looking for to decide when to go to the vet? I’m sort of on a budget now after buying them oxbow pellets and hay, so I’d like the vet to be a last option.