Welcome to BYC! Roosters will get a reddish tint to the comb fairly early, and also start to grow wattles sooner than pullets. Pullet's combs don't usually turn red until they are ready to lay eggs. Once the chicks feather out in 4 weeks or so you can post pictures on the Breed/Gender https://www.backyardchickens.com/f/15/what-breed-or-gender-is-this section for some opinions. Once the chicks have feathered out they can be moved outside. As long as they have a draft free coop they will be fine. Good luck to you. Also, you may want to read through the Learning Center, lots of great info there. https://www.backyardchickens.com/atype/1/Learning_Center
