Calci Worms

Hello. Over the winter, my garden starlings, blue tits and others have had a voracious appetite for dried and soaked mealworms, in a feeder and a mesh tray. For the past few days, I introduced some  calci worms as well and they haven't been touched at all. Is there any reason for this or are my visitors just fussy? I'm new to bird feeding so I'd be grateful to anyone who can advise me. Thanks.