A common question for a new owner is how big can the food they give their snake be. An easy and reliable rule of thumb that many people with snake use is as follows:
First measure your snake (a rough estimate is fine) at its widest part. This will likely be about midway along the snake’s body. Second measure the food item (again a rough estimate is good enough) at its widest part. This is normally across the back hips. Now compare the two measurements. They should be close to the same size.
If you use that estimate to gauge the size of food to give your snake you will never go wrong. That’s not to say that a snake can’t eat much larger or even much smaller food but that will keep it nourished without causing it to become obese.
Don’t worry about the fact that 9 times out of 10 the food will look like it is about 5 times too large to fit into your snake’s mouth. As you can see by the picture to the right that has absolutely no impact on the snake. Their jaws and skulls are designed to separate and allow them to ingest much large food than you might expect.