I am so sorry for your loss! Please don't blame yourselves - it was a true accident. I have had my girl for 9 years this year and all of my dogs up to this point have left her alone - except my newest guy, a German Shepherd. Ugh. He wants to catch her so bad and he got her one time (my fault) - I was clipping her nails and released her from the towel to fly back to her cage. She got caught up in the towel and went low and he grabbed her SO FAST! Thankfully no damage but it was then that I realized I had to be extra vigilant making sure she is locked and he is crated when we aren't home. And he is crated when she is out to fly. Please forgive yourself and grieve as you need to.