Hello and welcome to BYC!
Generally all young birds and chicks are leery of new foods. It's a protective mechanism built into their brains so they don't eat anything poisonous and die. So if they eat what they know didn't kill them yesterday, they will survive today.
However usually once one eats the treat, the others will eventually follow. And I do suspect these 2 birds that are not indulging will eventually join in. Pretty soon they will eat anything that drops from your hands and ask questions later! Ha!
But all this being said, there could be a couple of things going on here....it is possible these three are shy and at the bottom of the pecking order. They are too nervous to join in. So I might suggest separating them at treats time and see if they won't eat them when they are alone? Sometimes this is all they need to relax and enjoy a good meal worm treat. Make sure when you do feed the flock meal worms you have a big enough space that these two feel comfortable in joining in. If they feel cramped in, they might be too nervous to eat with the flock. (same goes with feeders and waterers...make sure to have several feeding and watering stations so nobody is bullied and you have enough space for the amount of birds you keep)
These three could also not feel well and food is not all that interesting. Usually the treats are the last thing they will turn up their beaks at, their chicken feed is the first thing ignored when sick, so keep an eye on them that they ARE eating and drinking properly, are just as active as the others. If so, I would say they need more time to adjust to new foods and their flock mates. All treats take time for young birds to get used to. Keep feeding them new things and eventually they will eat pretty much everything.
Good luck with your new babies and welcome to our flock!
