If they're not eaten down to the quick, close to the trunk and beyond the last bud on each branch, there's some hope. If they're going to do any regenerating, you'll see tiny green starts once the season gets going. Deer shouldn't be browsing them too much longer - once their natural food gets a little more abundant. (Vain hope!) This was a bad winter and lots of things were ravaged they might not normally go for. If they're alive and worth saving, burlapping them this fall would be about the best strategy

Arborvitae are just deer candy - I have two that are too big to wrap/protect so they get browsed up to the 5-6' mark. They regenerate over the course of the growing season - but never reach the nice look they had before they were browsed. I have 5 more in an out of the way spot that look like 8' all day suckers. When I can think of a good and possible semi-resistant alternative, these are all going to go!

The deer didn't make any attempt to nibble my new 2' Black Hills Spruce which I didn't protect - must be the short spikey needles. I picked those up very inexpensively at one of the big boxes.