chicks with pasty butt

I’m posting this for a friend of mind, so I don’t have tons of info, but she spotted worms in one of her little chick’s droppings, and she needs help finding a de-wormer.

I received 9 chicks from a hatchery, arrived USPS. After I brought them home they had super runny poops, and a few had developed pasty butt. I cleaned them up, and set them back in the brooder. They all started eating and drinking immediately. They seemed healthy, and lively. The next day they...