Different skill sets: one student played wind chimes, and really got into it. One student played bass drum and was very steady. Most I've put on percussion because they could find a pulse and not disrupt. I did have one on Bass Clarinet and they played six different notes, and only long tones (whole notes). Don't try to expect them to perform at the same level as others. Give them grace at their level. And, if they don't play at contest, it's ok. They are getting a band experience in class.