I don’t think it’s because you’re handling them less - that’s probably human guilt whispering to you. Mine go through phases of squeeking less (and then decide to zoom around the cage all night waking me up that way instead!).
I find that they squeak less if the times of the feeding varies, like they are confused as to when to squeak. Like when I have a week off work they get their breakfast a little later and they don’t squeak for it.
My next comment may be a bit weird but I find they are a bit less excited about their veggies right now as the veg isn’t as tasty as when it is in season (eg most salads - tomatoes etc) are much nicer in summer. Even the supermarket parsley is a bit floppy at the moment. They eat more hay now than in the warmer months.
I wouldn’t worry, unless they lose all interest in food and sit huddled in a corner and don’t bother coming out for food. Rustling a salad bag may do the trick!
I hope one of the above is helpful!