What is your general location? If your in zone 5A its probably way to early to Spring prune yet.

I'm in zone 6A and will not prune until April sometime...

But they probably still will grow back and be ok.
Were these older Knockouts?

You only have 1 week until April.
I have always done it around this time of year up here around Toledo.

Yes these are 6 or 7 years old.

It was a very cold Winter this year -26 at times.

The deer also liked them.

It's a bit early but it's done. I'm just north of Detroit and I won't prune for a while yet. I usually wait until the forsythias bloom. The problem with pruning so early is that we are still going to get some really cold weather and heavy frosts and freezes. Unless they're well mulched you could still lose more cane to that and end up with nothing left. Pruning also encourages them to grow and they may try to put out a lot of new growth that won't survive any freezes. this just uses up the plants energy for when the weather really does break. The roses can only do that so many times before they end up dying.

I just lost my snow cover last week and the ground is definitely still frozen. I would wait to fertilize them though. They're not growing yet and can't take it up anyway so it will probably just wash away before the rose can get any of it.

Don't worry about them coming back. They'll be fine. They may even come back better than ever. As long as there was still some green cane left on them above the graft they'll grow once things warm up enough.