Depending how old they are and whether they've eaten anything besides chick starter, some could be cecal poops. Every 1/10 (or so) poops is darker brown and kinda runny/sticky and is the product of the cellulose digestive tract that processes the fibrous plant materials they eat - leaves, grasses, pine shavings.... totally normal.
My day-old babies arrived today and have different colored poops as well. Most of them are electric to dark green/white which I'm guessing was due to the electrolyte gel in the shipping container. They'll get browner and more "chicken like" as they process their first days of chick feed.
Is this normal? 
