Breadcrumb Not Showing on posts

My guess is that where you placed the call to bcn_display() is only working on pages and archives. As I’m not familiar with your theme and exactly where you placed the call to bcn_display(), my guess is you added it to the theme’s header file (likely header.php), and, for some reason, posts don’t use that header file. You may need to check out your theme’s template files for posts (typically single.php or single-post.php) and either see what it uses for it’s header, or add the bcn_display() call to that file as well.