Bigger poos are always better. You should see the poos of the bunnies at the shelter--they're on a very hay-based diet because hay is healthy and cheap. They only get a little bit of pellets, and greens as a snack, but all the hay they can eat. Their baby and dwarf bunnies have poos as big as my adult medium-sized bunnies! I can tell when my guys are eating lots of hay by poop size. It's good that Butterscotch's poos are getting big! It's a sign of a healthy GI tract and a liking for hay, which always helps the rabbit.