My heroes disappear

Good afternoon. My heroes are trained in the camp and immediately disappear. A place for them in the barracks is enough. I simply do not see. What do I do?

Are you accidentally eating them? In order to lock heroes so they don’t get eaten, immediately “favorite” them in the Heroes tab:

The GREY tab above is unlocked. The WHITE tab below is locked. Don’t lvl heroes until you favorite the ones you want to keep.