Treat balls are a fun way for your dog to eat their favorite treats and get some fun exercise at the same time! Each of my dogs have their own "treat balls". I buy Vitakraft yogurt drops (available in vanilla, carob or peanut butter) and break them up in small pieces and put about 4-5 drops total in each ball. They go nuts with their treat balls! I love watching them roll the balls from room to room with their little noses and eating the trail of treats that drop out. They chase those things all over the house. All they have to hear is "yogurt drops" and they run to their balls because they know that's the only way they get yogurt drops.
I have 2 different treat balls. One is called a "giggle ball" which is a hard plastic and makes a goofy giggle sound as it rolls around. The other one is a softer plastic (but still hard if that makes sense) and it has dimples throughout it which lets my my min-pin, Alexis, "grip" and pick up the ball with her teeth and carrry it to another room should Sammy have the audacity to get too close to it.
This isn't the actual one we have but it's very similar. It has a hole on one side where you can put the treats inside and where the treats drop out of while it rolls around.
If your dog doesn't have a treat ball I highly recommend you let them try one - they will love it and you will get a kick out of watching them play with it!