Probably the very best thing to do is provide the trees with enough water to overcome this stress. You should even consider watering the trees in the winter if the ground isn't frozen. Don't over-water, but if the soil is dry and not frozen you should supply some water to the tree. Fertilizing a stressed tree as you describe would stress the tree even more. With fertilizer the tree will try and grow faster thus creating even more stress. Watering recommendations are listed on Woody Plant Management During Drought and with Limited Water Availability in Colorado. To specifically address the wildlife damage you may have to erect some structures around the trees to prevent the wildlife from damaging the trees. There are many repellents and other methods available. You can read more about them at Wildlife Bulletins. You can see which methods might work the best for your situation. As far as current damage to the trees you should consider pruning off any dead or damaged branches. You can do this procedure at any time. Prune back to live tissue.

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