Theme page alter function to force region template to render, even if no blocks are assigned to the region

force region render.php

<?php
function THEMENAME_page_alter(&$page) {
  foreach (system_region_list($GLOBALS['theme'], REGIONS_ALL) as $region => $name) {
    if (in_array($region, array('header'))) {
      $page['header'] = array(
                '#region' => 'header',
                '#weight' => '-10',
                '#theme_wrappers' => array('region'),
      );
    }
  }
}
?>