Reduce bot registration for WordPress

bot_register.php

//1. Add a new form element...
add_action('register_form','erwp_register_form');
function erwp_register_form (){
    $spam = ( isset( $_POST['fooey'] ) ) ? $_POST['fooey']: '';
    ?>
    <input type="text" name="fooey" value="<?php echo esc_attr(stripslashes($spam)); ?>" style="display: none;" />
    <?php
}

//2. Add validation. In this case, we make sure fooey is empty.
add_filter('registration_errors', 'erwp_registration_errors', 10, 3);
function erwp_registration_errors ($errors, $sanitized_user_login, $user_email) {

    if ( !empty( $_POST['fooey'] ) )
        $errors->add( 'spam_error', __('<strong>ERROR</strong>: Opps, this looks a bit spammy, please try again!','cheltsocial') );

    return $errors;
}