Snakes won't eat when they have had enough. I offer mine food as long as they show me they are clearly still hungry and when they are satisfied, they will turn away from food and ignore it totally. Generally they will pig out, sometimes more than once a week, then go quite a while without wanting to eat (usually followed by a shed, relieving themselves, then being ready to eat again.) I noticed in the wintertime, even indoors with controlled temps and lighting, all my snakes went several weeks without showing any interest in food whatsoever. They clearly were healthy and in good condition, just simply not hungry. (And when they started eating again, for a couple of weeks they definitely made up for the lost time!!!)
I have noticed, when talking to other snake owners, that all our snakes kept in different environments, different species, seem TO BE SYNCHRONIZED WITH EACH OTHER! All these different snakes seem to get hungry at the same time, all shed at the same time, within a few days of each other. It would be interesting for people here to tell when their snake is hungry or when it's shedding to see how widespread this syncing among snakes is. I have noticed my own snakes becoming restless before a thunderstorm or major weather change comes. One night all my snakes stretched themselves out in their cages and buried their heads in their substrates, a behavior which I'd never seen before or since. A few hours later that night an earthquake struck strong enough to shake and knock a few things off of shelves here. Clearly there was SOMETHING the snakes sensed and reacted to, before the actual quake hit.