I adopted my second chin 4-year old Jeffy in January from a neglected family; quarantined him for almost 2 months; put the cage side by side for 2 months; let the chins smelled each other in the 3rd month, housed the chins successfully in the 4th month.
I took it slow while my bf urged to put them together as soon as we got Jeffy. BUT during the introduction time (about 2 months), our first chin Chester got his little fingers bitten by Jeffy twice through the cage's bars, we went back and forth to decide if it was intentional or accidental to a point that we thought they should not be housed together ever. We still did not let them play together at the time. They had their seperate play time. And we were planning to build a brand new 5 feet cage just for Jeffy.
BUT, We noticed whenever Chester was let out and play, first thing he did was to go check out Jeffy, somehow Chester kept going back to see Jeffy even he got bitten twice! So we thought they must have liked each other....
One night we just knew it was about time to let them played together,we made sure that they were in a spacious room because we found that Jeffy was too eager/aggressive when the room was small (e.g.bathroom). So they ran around the living room and gradually they became inseperable
We did not do the cage swaping, changing toys...etc
I think, we were kind of lucky, Chester is a mellow younger chin, so it was easier for him to accept a new chin. I do not have alot of expereince introducing chins but we got luck! So good luck to you! :wink2: