SergeyCorpus

<?php $query = new WP_Query( array(
  'post_type' => 'service', // name of post type.
  'posts_per_page' => -1
) ); ?>
<?php
$programm_posts = get_field('programm_posts');
if( $programm_posts ): ?>
    <?php foreach( $programm_posts as $post ): 
        setup_postdata($post); ?>

<?php 
$children = get_children( array(
  'post_parent'    => $post->ID,
  'post_type'      => 'service',
) );

echo count($children);

 ?>

 <?php endforeach; ?>
  <?php wp_reset_postdata(); ?>
<?php endif; ?>