You haven't said what type of conifer they are, but generally, if they're going brown and they're in pots, they've either dried out too much at some point, or the compost in the pots froze for too long during the tough winter. Most conifers don't put out new growth on old wood, so cutting them back won't work. You may want to replace them - even if they're not dead and they continue growing, they won't look very attractive.

If I were you Id put on a good pair of gardening gloves and give them a ood rub allover to get rid of the old dry stuff and continue watering and feeding them! we have quiet a few conifers in the fron garden, and one very large one that my husband shaped too much!!!!!!!!!! looked dry and brown I thought it was a gonner, but Ive noticed that it is starting to green up again , so dont give up on it yet, we have had a very hard winter and lots of things have taken a thrashing! but nature is wonderful the way things can recover.