loosing needles on a spruce tree
We can't be sure what's causing the needle loss on the branches shown in the photo. For a certain diagnosis, consider asking a forester or certified arborist to assess the trees' health onsite and recommend a course of action.
That being said, based on what we can see in the photos, it's possible the trees have been affected by a common spruce needle disease called Rhizosphaera. By reading about the symptoms mentioned in the following bulletins and looking carefully at the needles, you may be able to determine whether the disease is present.