And both Cheech and Chong love it. I thought Chong would because I tried him with a wheel (it was a plastic rat wheel and I gave him very careful supervision to make sure he didn't chew it. It was a test, if he used it I would pay for a proper chin wheel, but he just ran on top of it and I was worried he would hurt himself, then he started to chew it so I took it out.) Cheech I thought would hate it because she hates anything new. She ignores anything new I put in her cage for months until one day you wake up and it's been chewed to bits.
It was so funny watching them in the ball for the first time, they were all wobbly. I opened it at one end and put that end near the open cage. It took a long time for them to venture in the first time, but the more they're out in it the quicker they jump in when I offer them the chance. They've even worked out how to get over the frame at the bottom on our doors by running really fast. It was a gamble but it payed off and now I have two very happy chins who can get even more exercise, but I limit it to 20 mins at a time in the ball to make sure they don't overheat.
They still don't like each other though.