Balls are pretty much solitary animals by nature and only come together to breed. Most people recommend against housing them together mainly because it could cause stress in the snakes which could lead to a variety of illnesses and if one gets sick, they will both get sick. Yadda Yadda
With that being said, it can and has been done. If you are responsible it can be done successfully, if not, you'll end up with sick (or worse) snakes. I would recomend against housing two males together as they may combat when they reach breeding size. I've seen many people house two females together without incident or a male and female (but then theres the breeding thing you have to be ready for). It's extra work to house two snakes together (the bigger cage in general is a pain in the a$$). You have to provide enough room that they can seek solitude if they want, they need to have their own hides in hot and cold areas, it's important that they don't have to compete for basic needs. They need to be removed from their cage and fed separately. If you get a pair of hatchlings and raise them together then they will be more likly to adapt to (and maybe even find comfort in) the other snakes presents. Hope this helps.
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Tosha 
8.10.0 Ball Python (Harry and Fluffy and currently un-named)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Dessert Tortoise (Pope)
7.9.5 Fish (1,2,3,4...)
0.0.1 Frog rescued from pool skimmer
0.0.2 Lizards rescued from pool skimmer