I'm filling a space right now as well and one of the people coming for an interview asked me a few questions about why I had a space come available unexpectedly. I was very vague and based the answer on my principals and what I need to happen with the daycare families and explained that the family I terminated was not meeting my standards. But I would never breach client confidentiality either. It's tricky! You should be able to state without fear that you will not tolerate aggressive behaviour at your daycare. I don't see a problem with that. Tell the truth.