Going to tell my mother about violont, murderous intrusive thoughts. What parts should I tell her?

Hormones. Too much estrogen, the female hormone, and you are male. You like chicken? What do you expect your mother to do? If you did something to your mother because of this, it would be nice to let her know why. But, everything that has happened to you has been caused by you. What you put in your mind is like hiring actors for the show in your head and they will take over your thoughts because they are your thoughts. Fire those actors and replace them!