Fern, I wouldn't worry about them yet. If they made it last winter, they are more established now. When the other trees start budding, they should too.
Brown stems doesn't mean they are dead.

Shelley

PATIENCE!!!!!!!!!!!!!!! I wouldn't even think about them for another couple weeks. If they haven't budded out by early to mid-May, still don't despair, they can still bud out from underground stems and roots into June.
-Don

Voice of experience - i was sure that Henry Kelsey was dead last spring but when i dug him out, there were shoots coming from one of the roots. Looks like that baby has made it through - there are green rose leaves in the pot that's buried in the ground. I found some green on the canes of Morden Sunrise and Delicata, but most of my roses are still pretty much buried, if not in snow then in their boxes full of leaves.

Thanks for the words of wisdom. Deep down I know that it is early it is just that they all emerged from the snow last year and were actually a lovely definitely alive shade of green - patience is a virtue that I will work on

Fern

Fern,
They'll be fine, just cut 'em back hard this spring and watch them take off! We had good snow cover here in the city, the crowns will make it :)
Also, you might have Prairie Dawn instead of Prairie Joy if it was growing over your six foot fence!
Koren in Saskatoon

You can also scratch a tiny piece of stem and if it green underneath all is well.