If you have thought about what you would reach by breeding you can start to build up a breeding. If you have two young ones normally it´s pretty easy to bring them together. Normally you put them together in a cage and short time later they are used to each other. But you should be careful to bring together male and female before being 8 - 9 months old after reaching puberty. If you bring them together in a younger age it can happen that the male, right after puberty, is going to copulate the female, which is just to young then. Bringing together two older ones is a little more complicated. To ease the bringing together they should be put in a cage which is foreign for both of them. Additional it is helpful to disturb their sense of smell by putting some tooth paste or perfume on their nose. Often they loose their sense of distinction and accept to have a new partner. Nowadays breeders often do colony-breeding, that means that one male is together with two or three females. Often this works out pretty good, especially when all of them know each other since they were young, but it can also happen that one female if another one is having babys is biting, injuring or even killing them. Once it happened to me that a baby was injured very vehement and since that time I only have pairs together. Commercial breeders often do polygam-breeding, that means that one male has four up to six females. The females are sitting in an enclosure and every female has her own cage. The male has not an own cage, he "lives" in the gangway from where he can reach each of the females. The females all have ruffs to prevent them from coming into the gangway or the other cages. For me it is no question not to do such kind of breeding, because I try everything to give my chinchillas as much freedom as is possible, that also means to give them big cages.