Add excerpts to Pages in WordPress

add_page_excerpts.php

<?php 

/**
 *
 * Add support for excerpts to Pages
 * @link http://codex.wordpress.org/Function_Reference/add_post_type_support
 * $post_type (string) is a registered post type. In this instance, 'page'.
 * $supports (string or array) includes:
'title'
'editor' (content)
'author'
'thumbnail' (featured image) (current theme must also support Post Thumbnails)
'excerpt'
'trackbacks'
'custom-fields'
'comments' (also will see comment count balloon on edit screen)
'revisions' (will store revisions)
'page-attributes' (template and menu order) (hierarchical must be true) (the page template selector is only available for the page post type)
'post-formats' add post formats, see http://codex.wordpress.org/Post_Formats

 */

add_post_type_support( 'page', 'excerpt' ) 

?>