Question on ventilation

My girls are growing in the bathroom, in the separate room where the tub and toilet are. I have foil over the window for light and nosy neighbors. What would be the best way to ventilate, it's not a tent where I could have a 4"hose venting the heat and smell. I was thinking about venting up into the attic but I'm afraid it will make the whole house stink. Can I just crack open the window and direct a big fan at it? Any advice?

get heating duct cut a hole in drywall to ceiling get a charcoal filter to go first then duct then fan then duct to attic it will take out the heat and smell