I have 10 australian spotted ducks that are 3 weeks old. I have a coop about ready for them. Currently I still have a heat lamp for them in the brooder. Do I need to put that in the coop? It's only getting down to about 75 degrees at night. They are currently just starting to show feathers. The breed supposedly matures in about 30 days. Also, if not a heat lamp, should I still keep a light on in the new coop for a while to keep them calm? New the site. What a wealth of information!