Ok so I have a few quick questions. First, what age can I stop using a heat lamp on the chicks? Currently I have 4 almost 3 week old Orpington chicks that stay in a cage in the house. They never stay on the side by the heat lamp and it stay about 70 in our house. Can I stop using the lamp? Second, we are getting 2 3 day old EE chicks tomorrow and I'm wondering if I need to keep them away from my other chicks or can they stay together for warmth? Lastly, hold old do buff orpingtons and EE chicks need to be before you can sex them?