they can definitely stay healthy on what you are giving them for now.
i would make up a schedule sheet for each one of them and start recording when, what, and how many you feed them that day. i also like to include a column for when i notice they are in blue and also for when they shed. then once you get a scale you can add a column for weight. i weigh mine after every poo. this way my weights are as accurate as i can control. this is a good way to monitor growth. you will find out if you are not feeding enough if your snake does not put on weight.
also a comments column comes in handy for those out of the ordinary observations.