If my 8 chicks hatched on August 14th an 15th, how old will they be? I know the answer is 3 weeks but my MIL apparently cant flippen count an just got on me lastnight about my chicks having a light on them outside in below 60*F weather and raining! she yells at me saying "you need to toughen them up for winter an their older then 3 weeks" you cant toughen a baby chick up. you'll just kill it. so yeah I just want to make sure that my counting an recounting is correct an that my chicks really are 3 weeks old.