I would not de-worm very young chicks. I generally de-worm only once/year for my entire flock if I feel the need. This year has been extremely wet in our area so I will de-worm this year. My chicks were hatched around March 1 so I will wait until July to de-worm them, before they start laying. Then I will de-worm my existing hens in August before they move on to their new homes.
Generally, I do not de-worm on a routine basis unless I have suspicion, see something while cleaning the poop board. Then I will collect a specimen from several birds' droppings, take it to the vet, and let them identify the type of parasite present so I know what type of de-wormer to use.