Hi, I have set up my brooder in my back shed, the temp goes as low as 2 degrees C at night, i am hoping to hatch about 20 or more chicks, standard and bantam sized and i was wondering how many heat lamps i need? What wattage i need to buy? Is the dome needed? Is there any way to keep a stable temp if it varies from 4 to 15 degrees C? Thanks in advance and im sorry if these have been asked before.