For allpages-locked heaps, page allocation is generally sequential, unless pages are deallocated by deletes that remove all rows from a page. These pages may be reused when additional space is allocated to the object. You can create a clustered index (and drop it, if you want the table stored as a heap) or bulk copy the data out, truncate the table, and copy the data in again. Both activities compress the space used by the table and eliminate page-chain kinks.
