@ AJA: no tr. cristatis is a very calm species that likes to stay in the trees. They wander around in their large ficus tree, and on the ground floor of the enclosure (which is 1m20 L x 1m20 W x 30cm H). The 30cm height keeps them in the enclosure and they never risk to jump over the edge out of the tree.
I'm keeping them like this since i've obtained them in february when they were 2 months old. They've been together since without a problem (1.4 CB group). Recently i've obtained a 2nd male (subadult) and he fits right into the group without a problem, no stress, no aggressiveness from both sides.
@ Rocky: I keep them in a large ficus tree of 2m50 H x 1m50 W, with a ground floor as described above. They like to sit in a group at the lowest branches of the tree very close to each other without signs of stress (no hissing, no dark coloration/patterns). The only thing that is tricky is to hand-feed them since you need to make sure that they don't shoot at the same pray, but since they are very calm they are handled easily and i can move them further away from each other if necessary (although i never handle them if not needed).
best regards
Joery