I'm expecting a shipment of chicks to be delivered on Thursday and I'm planning on brooding them in my new coop using the heating pad method. I'm in Oregon and I'd like to see how others have set up their heating pad brooders, whether they're in coop or not. This will be my second brood of babies and my first using the heating pad method and brooding them outside rather than in my house or garage. I ordered 9 but I'm expecting some extras as "packing peanuts" so I was wondering how big I should make my brooder. Would 4'x3' be big enough for them?