I don’t know how she came up with this method for emptying her treat ball, but it’s very effective.
[ETA: I guess you have to click through to see that it’s a video and not just a photo. Hmf.]
I usually fill it with carrot slices. This is about half a carrot, and the pieces are hefty dnough to not stick to the inside of the ball, but small enough to fit through the hole when it’s compressed flat.
You can also fill it with large kibble or treats. Iams mini bone biscuits are the perfect size, but I feel like carrots are a healthier option.
The ball is made by StarMark and is apparently indestructable.
red paper boat 
Don’t know if cucumber would work, but my dogs love cucumbers! They like carrots but “supposedly” they are fattening because of their sugar content.
LikeLike
With smaller dogs, the sugar might be an issue. Carrots are also full of fiber, though, so I wonder if it evens out?
Frances LOVES cucumbers. They might get too mushy in the ball, if the dog isn’t in a hurry to get to the treats.
LikeLike