Adam Harley (Kawauso)

Enables excerpts as a feature of the ‘page’ post type, adding the Excerpts meta box to the Edit Page view automagically. This readme is about as long as the entire plugin.

Page Excerpts for WordPress Three

Add excerpts to pages the WordPress 3.x way. Less code, less overhead.

J0SiE

Created to help those people who don’t like to edit code in template files (or are too lazy to do that). 
Just activate the plugin and it will automatically show the_excerpts in your homepage, archives and search results. 
It tries to display your custom excerpt text and if it doesn’t find it it will show an automatically generated excerpt. 
You can also define excerpt length, custom read more link and attach a thumbnail.

Auto Excerpt everywhere

Thanks to author for creating this plugin. 
It's works out of box. And working fine at WordPress Version 4.6.1


Works out of the box on WP Version 4.6.1

The plugin automatically displays excerpts instead of full post contents in your blog. Custom excerpts and generated excerpts supported.

Page Excerpts for WordPress Three vs Auto Excerpt everywhere