Feed him in his enclosure. Moving him to feed him is an additional cause of stress. The only reason I've ever heard that is even semi-valid for moving a snake to feed it is to avoid swallowing substrate. But, snakes swallow "substrate" in the wild and it at least mostly doesn't hurt them.
Having the snake by the window will just cause temperature swings. It can get extremely hot if direct sunlight hits his tank during the day, and it might get quite cool at night (expecially in the winter). I'd suggest moving it further from the window.






