You can encourage more participation by workshop attendees around more sensitive topics when you use creative techniques for soliciting feedback and encouraging active engagement.
Try a favorite exercise called, “Behind Your Back.” Give everyone a post-it. Ask your question and have participants write their response on their post-it. Collect all of the post-its. Mix them up. Place one on each participant’s back. Stand participants in a circle facing the back of the person on their right; have each person read what is written on the back of the person in front of them. This is particularly effective when dealing with questions or comments people will make “behind someone’s back” but not want to say to their face.