I'd up it to 15 if you are hatching the eggs. If you get 12 to hatch, you're doing fine. Loose 1-2 keets and now you're down to 10. 2 move in with the neighbors....down to 8. Guinea math. I started with 13 keets and ending up with 9 by the time they got out of the brooder. Haven't lost one in a year.