I have 2 call ducks that I got this spring, it's starting to get colder and colder during the nights ranging from 30 depress to 10 degrees Fahrenheit. Do they need a heat lamp on at night? I have one on them now that they are separated ( one is plucking the others feathers out ) I have a heat lamp on them that is for both cages. I'm new to ducks so I'm not sure what kind of light they need, they have a pen outside that they go in during the day and at night they are in the garage in a rabbit hutch. What else can I do to keep them warm, or how much light/warmth do they need?