Well there's only two things on the menu, rats and mice! The size should be about 5% to 10% of the weight of the snake (don't really need the chart), or a rodent about as big around as the biggest part of the snake unless you have a really big snake, then I shoot for about 150-180 grams max for a ball python. You can feed frozen thawed, just make sure it's totally thawed out and warmed to about 100F before feeding, or you can do fresh killed or live (just don't leave a live rodent in with the snake for more than about 20 minutes).