How to add crumb for each search result item?
If you already have a function to get breadcrumb from URL and assuming breadcrumb is, when is it, customize by hook_menu_breadcrumb_alter hooks, you just have to call this hook :

// Allow modules to alter the breadcrumb, if possible, as that is much
// faster than rebuilding an entirely new active trail.
drupal_alter('menu_breadcrumb', $active_trail, $item);


If this isn't enough to fix your problem, you can also see this contribution on github which seems great regarding the default breadcrumb construction in Drupal : https://gist.github.com/arshad/5490042#file-gistfile1-php-L12

Hope that helps :)