If you are new to Hognose, I would advise you to start with only one until you gain the experience necessary to maintain this Genus of snake (I am assuming you are referring to Heterodon). Contrary to what many say, no single species of North American Hognose is extremely difficult to care for, however, you need to be aware that they can be considerably more demanding than a Corn or similar species. This is especially true if you intend to start with an Eastern. Do not under any circumstance house two Hognose together as a permanent arrangement (a male and a female Hognose may be placed together only when they are being bred under close supervision). As far as the size of the enclosure, unless you have an unusually large specimen a ten gallon arrangement will suffice. This is ample room for an adult Hognose of any North American species as they rarely utilize the space they are provided to its entirety.
Good luck!
Jennifer Webb
(Jungle Gems)