It is generally recommended that you keep each snake housed separately. I know some people who house them together, but I will never house mine together (except for breeding them) for health reasons.
Health reasons:
They have been known to be cannabalistic.
If one has a disease it can easily be spread to the other one.
If one regurgitates or has some other problem (eg. bad looking feces, etc.), you won't be able to tell which one is sick.
They can be stressed out by each other.
If they are male and female, they may breed too early, risking the life of the female.
And I'm sure there are other reasons, but I can't think of them now.
If you really do want to keep more than one snake together I would pick 2 males or 2 females, 2 females being my choice. I say this because once they get to be adults, if you have 2 males, they may fight each other when breeding season comes around, even if there aren't any females around.
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alstiver@hotmail.com
1.0 '01 Hypo snow cornsnake (Tesla)
0.1 '02 Ghost (pastel) cornsnake (Banshee)
1.1 '02 Bloodred cornsnakes (Desi and Luci Too)
0.0.4 '03 American toads
0.0.3 Goldfish (Kabuki, Isamu, and Yuki)
1.0 American Eskimo mutt (Rusty)