Check their stats. Some like Chungkingosaurus and Dracorex can be moody and require special care so just a heads up.
This.... this this this.
I found that out the hard way... with Ankylosaurus...have a pen that is too small, with too many other Dino's in there and oooh boy those ladies are cranky. I had one that just kept escaping, didn't kill anyone, just generally went for a gallop around to snarl at some weird looking two legged two armed creatures that she sees outside her pen.
At that point I only had 3 paddocks... 1 for herbivores and 1 for Carnivores, and 1 mixed as an experiment aaand she'd probably not enjoy being in the other mixed pen since there were already two of her species in there and a third would annoy them... those two already spend a good amount of time warding of the Dilophosaurus... Id rather not upset the balance and have a Dilophosaurus follow an Ankylosaurus out of the paddock, spitting on and eating all the guests.
Rule number 1... keep them happy...
Rule number 2... keep them happy...
Rule number 3... if you cant keep them happy, feed them to the biggest Carnivore you have in the park.