Die back on white spruce and Norway spruce
Unsure if this is normal die back or this is an issue that needs attention with some insecticides. I have only a few trees that have this, but I want to stop any other trees of getting this if it is a disease.
There are a number of things that can cause the interior needles to turn brown. This can be do to the weather, if the soil is too wet or dry, nutrition, insects or diseases. Unfortunately, I can't zoom in enough on your photos to tell if the browning is being caused by an insect or disease. Here is a link to a nice publication on Spruce problems that may help you to diagnosis the problem. https://web.extension.illinois.edu/plantclinic/downloads/Plant%20Clinic%20Report%20Spruce.pdf
Also, you could send a sample to MSU Diagnostic Services -www.pestid.msu.edu to have them identify what may be going on. There is a charge for this service.