B-52s that are not in service demolished?
No, some B-52H's in long term storage at the Aerospace Maintenance and Regeneration Group are in Type 1000 storage, which means,


  Aircraft stored in near-flyaway condition. Can be stored without re-preservation for a period of 4 years. Aircraft stored under this category may be downgraded to Type 2000.




Note: This screengrab is from Google Maps and I'm not sure when it was taken.

The USAF is under the process of reclaiming a B-52H from the Boneyard as a replacement. 



Source: foxtrotalpha.jalopnik.com

However, all the B-52G models have been destroyed in compliance with the New START treaty.