I have been actively breeding both Norways and ASF. ASF are much cleaner. Although I have to admit the Norways are more fun to work with. You can interact with them and their babies are adorable. I breed both, as different snakes are on different diets.

1. Litter size: In my experience ASF have much bigger litters. The smallest litter I have ever had has been 7 and the largest has been 21! Where as Norways give me usually between 6 - 12, with my largest being 13.

2. Cleaning: I end up cleaning out my Norways every 5-7 days, depending on whether or not there are pups in the bin. Where ASF's get cleaned out usually every 2 weeks, right now I have a colony with 35 babies, and they only need to be cleaned out on a weekly basis. Huge savings on time, and bedding.

3. Food: Norways are big, and eat MUCH more in my experience. I have to fill my Norway Hoppers, where there are 3 females, every 2-3 days. Where most ASF colonies without young make the hoppers last about 7 days.

4. Growth: Norways reach "large sizing" within 3-4 month which is the same as ASF. However a Large Norway rat is substantially bigger than a large ASF.

5. Breeding: Norways usually spit out a healthy litter every 2-3 months if given appropriate rest in between. Where as most of my ASF females will give me a litter every 1.5 - 2 months. ASF's are colony animals and don't need to be given time to recover from pregnancy.

6. Prey: ASF will usually get a better feeding response from your ball python - however, for a big female like my 2300gram spider, you end up feeding 4-5 adult ASF a week, where Norways will be able to grow to the size that is appropriate for a single prey item.

I personally like breeding ASF. It's much cheaper than buying them, where as Norway is readily available for cheap prices.