The first "Chin's Out" taught us well ... We "found" our first chin to get loose, in the top drawer of the filing desk ... I heard her having fun chewing up the paperwork in it, or who knows how long she would have been out.
She crawled up under it, then did the "spider-man" thing and scooted up the back side of the drawers until she reached the top one ... which had bunches of papers to nibble.
Also, be aware that they can learn to unlock their cages with the normal latches ... they just pull back and up and "pop" it open. We had one chin so proud of being able to do this ... she definitely showed us while we were looking straight at her.
Then, there are the other pets that help your chins get out. Lady, our Great Dane, would get lonely when we went shopping, so she would open one of the cages, let the chins in that cage out to play with her while we were gone. When we came home, she would take us to the open cage, then to where the chin/chins were hiding. She did this for almost 3 months before we caught on to what was going on. One of the pairs started fussing when we put them back in, Lady went over to try to calm them. They just kept fussing ... I guess Lady understood what they were saying, because she opened the door for them!
They are smart and ingenious at getting out and at finding places to hide. Please make sure you do not let your little one play in areas/rooms with cedar, cherry or many of the "hard woods" furniture. They will chew on anything, regardless if it is good for them or not.
Welcome to the "Chin-Hunt" side of chinchillas!
Jo Ann