Hi, brand new. I have baby chicks close to hatching from a friend. I have a ceramic reptile heat lamp with a red 150watt bulb, and thermometer to check the temp. The brooder box is a metal dog cage, with the heat lamp securely clamped on top. However, i need to wrap something around the dog cage to hold the heat in. Is it safe to fold a plastic tarp and clamp it half way up the cage? Other than that i was thinking of having acrylic cut. I am scared of cardboard. A plastic bin would be too big for the cage's height.