Get them something easier to stand on so they don't get spraddle leg, like pine shavings, sand, etc. Cute babies, you'll be amazed at how fast they change!
I learned that corn meal makes a good chick grit. A tiny amount of it in the crumble and some apple cider vinegar in their water (1 teaspoon per gallon) helps them develop gut flora and avoid pasty butt. Always seems like 1 chick will have pasty butt for a couple of weeks, stay on it. Backed up poop can be lethal. My cochin pullet still hasn't forgiven me for the pasty butt cleanings the first two weeks:Also just a preference of mine is to offer them greens at about a week old for a treat, but if you do that then they will need a small bottle lid of sand for them to eat and digest in their crop. They don’t have teeth to chew, so they rely on grits.
I'll second the vote on a heat plate. I got a infrared one from TS that had feet on itthat could be adjusted as the chicks grew, and it could be switched to a vertical design to be used with older chicks as you wean them down on temp or even for adults to supplement heat in a winter coop. I was very pleased with it, and it became their first roosting bar when I changed to a vertical setupDo you have a brooder plate or heat lamp set up for them? They need to be kept between 90 to 95 F for the first week. The plastic bag is a little concerning as well.
Getting them used to being handled now makes it easier whenthey are grown up if you have to give medicine, treat wounds, etc. They will love to be close to you and your body warmth. This one fell asleep in my lap more than once!Scared? What are they going to do, eat you?? Chicks are the most sweet helpless things, and if you can get used to them now then you can get accustomed to them as they grow into adults. Have them one at a time sit on your lap while you sit on the ground or couch, and you can let it sit on your hand.