It just struck me. Why should I cut down beautiful spruces? They are 15 ft tall. Is Spring pruning a good idea? Can I prune them on the top and sides?
Only the outer parts with foliage still present can be expected to sprout from behind pruning cuts. Therefore, you will be mostly limited to shortening the new growth each spring, shearing lightly so as to minimize the nearly inevitable production of an obviously unnatural geometry and crispness. Cut part of the way through the length of the new shoots, before these have become rigid but not so soon that they are spoiled by the operation.
Did you know that dinosaurs are believed to have munched heavily on needled evergreens?
They do not respond well to pruning except at the very tips to make them denser ... at best you can slow their growth down, but you are more likely to kill them.
It's a huge species, growing easily 50-80 feet tall and 20-30 feet wide at the base. If it's getting too big for the spot, remove it and plant something smaller. There are dwarf and compact varieties of blue spruce that will not overgrown your yard.
http://www.pnwplants.wsu.edu/PlantDisplay.aspx?PlantID=253 Sester's Dwarf Spruce
Here is a link that might be useful: Blue Spruce