Does insurance cover cracks in your foundation?

It depends on several factors

What caused the cracks

What are the ramifications of those cracks.

If the cracks were caused by a covered peril and there is actual damage beyond aesthetics then yes it would be covered

Bear in mind though that all concrete structures will develop cracks. It's a natural occurrence that generally has no effect on usability. So long as the cracks do not adversely effect the structural integrity of the home there is generally no need for repairs as this is a natural and expected occurrence.