I agree. I don’t know what those leg bands look like, their purpose, or what materials they are made out of. If you don’t need them, I suggest removing them now, but they might be the way you tell the chickens apart.
If you keep them, just keep checking them as the chicks grow. They may or may not get too tight. As long as the bands can move up or down the chickens are doing fine. But get rid of them if they start to get snug.
I use colored zip ties to mark mine after they reach a certain age, but occasionally I have to remove them and replace them as the chickens grow.