Wood and Couch questions :)

Hi all....

Just a few random questions....

I know the chins love to chew on wood but do they normally eat the entire thing or just eat the bark off?? Mine seem to eat the bark from their sticks and then are not to interested any longer...

Also, I have found one of my babies to be a Houdini :) I let them out for short play times since they are still young. My smallest will try her hardest to get over the barriers or sneak out of the cage/room and she will run to the living room and dive under the couch...This leaves me sitting in front of the couch waiting for her to come out, fuming, as I dont want to leave her unattended... ERRRRRR...

Any ways to curb that behavior/tips on blocking off couches???

Thanks,
Dani