If you are positive that you don't have capillary worms, you can give a really low dose for five consecutive days with a zero-day egg withdrawal. That dose will treat roundworms & cecal worms only, it will not treat capillary worms. I did a thread that explains how to dose a flock by putting it in a mash:Okay, I have not looked at dosage, yet, but I will later today and get back with you. Thanks!
Safeguard Mash - Zero Day Egg Withdrawal
@KsKingBee, who does his own fecals, does this:
https://www.jefferspet.com/valbazen-oral-suspension-500ml-w-cap/pFor large groups of birds, 20 ml per gallon made fresh daily. Give for two days and repeat in ten to fourteen days will kill round and cecal worms. To kill all types of worms give for five days and repeat for five more days within two weeks.