Yes, they do serve as great deer food here in NJ. My local deer have come right up to my house and driveway to eat them. But getting back to your current question, have you been watering them? We are in currently suffering from some degree of drought in NJ and July has been quite hot. Can't go wrong with propper munching though. Assume they may recoup if it starts to rain again. Good luck!

How long have these trees been in the ground? From the looks of them i would guess 5 or 6 years which is about how long it would take for an arborvitae to really show symptoms of being planted too deep. you may also want to check for mouse / chipmunk damage (chewed bark) at the base of the tree. these are the initial things I would look for.