Just leave them in this cage they will calm down. The head damage is probably caused from the flight factor when being scared they fly up and away and they must have bonked their heads on the cage wire. Might be a good idea to place them in a larger enclosure or garage at night. If this was a dog he might come back but if its was a fox or other wild animal most certainly it will come back, gate open or not. Especially if it was a raccoon. Good luck.
