Add it to fields/transparent/transparent.php. Add it to the blueprint with type: transparent

transparent.php

<?php
class TransparentField extends BaseField{
	private $fields = null;
	private $hidden = 0;
	private $hidden_empty = 0;

	public function __construct() {
		$this->type = 'transparent';
	}

	public function init() {
		$this->fields = $this->fields();
		$this->hidden();
		$this->values();
	}

	public function content() {
		$this->init();

		$hidden = brick('div')->append( brick('strong')->append('Hidden fields: ') . $this->hidden . ' / ' . size( $this->fields ) );
		$empty = brick('div')->append( brick('strong')->append('Hidden empty fields: ') . $this->hidden_empty . ' / ' . $this->hidden );

		$html = $hidden . $empty;

		return $html;
	}

	public function fields() {
		$blueprint = kirby()->roots->blueprints() . DS . $this->page()->template() . '.php';
		$fields = Yaml::read( $blueprint )['fields'];
		return $fields;
	}

	public function hidden() {
		foreach( $this->fields as $name => $field ) {
			$type = $field['type'];
			$value = $this->page()->content()->get($name)->value();

			if( $type == 'hidden' ) {
				$this->hidden++;
				if( $value == '' ) {
					$this->hidden_empty++;
				}
			}
		}
	}
}