Finding nothing on your particular issue, you are wise to pay attention to the health of your trees. Colorado blue spruce, not native to our region, are native to the higher elevations in the west. They are subject to a variety of disease and insect problems in Michigan, and much has been written about it in recent years. Unusual growths as you describe are often the result of stress, stresses that can come for a variety of reasons, most often droughty conditions from the previous growing season, but can arise from numerous varied sources.

Spruce decline has been a particular problem in Michigan and we recommend the services of a professional, such as a Certified Arborist, one who specializes in everything woody. I stress certified because anyone can call themselves an arborist and ISA (International Society of Aboriculture) Certified Arborists undergo rigorous training and testing. You can find one or more certified arborists in your zip code at www.treesaregood.com  Click on Find an Arborist.

Arborist evaluations are not expensive and he/she will evaluate everything in your landscape while there. A positive ID will give you peace of mind and periodic evaluations by a certified arborist can be invaluable to the average homeowner.

A second option, always available, is to send a plant sample to Diagnostic Services which usually results in a positive diagnosis.  https://pestid.msu.edu/ 

Otherwise here are a couple of links to more on spruce decline in general:
http://msue.anr.msu.edu/news/whats_going_on_with_blue_spruce     

http://msue.anr.msu.edu/news/what_is_spruce_decline_and_what_should_you_do_about_it

Good luck!