I personally will always get a pet from a shelter/pound/take one in that needs to be re-homed over a breeder any day. I have a problem with breeding pets, and i know several in these forums disagree with me. I just cant condone the idea of bringing more into the world when so many are already alive and out there desperately searching for a home. And you know what happens at shelters if pets don't get adopted. So i would rather save the ones we have then bring more into the world.
As for single vs pair; that depends on what you want and what your able to handle. Chins can spend a life time together without problems, or they can one day turn on each other. Either way you have to be prepared to separate them at any given time. (Two cages or something like a Ferret Nation cage that can be split into two. It's also a good idea to have two feed bowls and water bottles in a cage to reduce any chance of fighting etc.)
I've had a lot of social type animals over the years, so i have always been partial to pairs myself. But a good example, my two ferrets that live together recently had to be separated. While they get along, one is going blind and the other has started bullying him on occasion. Stuff like that is hard to plan for, but thats why i kept an extra cage around. You never know.
As for the age of a chin being older, i wouldn't worry about that too much in terms of bonding with it. It will take a lot of time no matter what way you go. You just have to be patient. My first chin that i took in was of unknown age. He was a full grow adult that had been passed around from owner to owner for a long time, so i know he was well past 2 years old. He was so stressed out when i got him that he would freak out if you so much as walked near his cage. With patience and work tho over time he beyond mellowed out. Now, out of my 5 chins, he is the most friendly and personable guy of them all!
Finding a good vet ahead of time as others mentioned is a really good idea. It is not something you want to be running around franticly trying to find at the last minute.
And learn your sexes. On a chin they can be surprisingly hard to tell. And ppl often take in what they were told is two same sex chins, only to find a baby one morning. And take my word for it, it is not a surprise you want to find out to late. It is purely luck that my first kit survived. He escaped his cage and hid under my refrigerator before i ever new he was born. (before i even new she was pregnant.) My ferret actually found him one night when she was out to play. And to this day i still shudder to think what would have happened if she hadn't. - So don't take there word for it. Learn how to tell and check for yourself, whether its a single chin or a pair.
