pekins ween off heat quickly, they might pant sooner than other breeds of ducks, and they grow fast but ide think that 2x2 will be fine for the week or two youll have them in your bedroomThank you for your insight and I will make sure to heed your advice. As discussed by @Jpat I plan to move the heat lamp(s) to only one side of the brooder. The 2x2 box was a panic build to make sure we had a warm spot for ducklings right on arrival. We recently built a full new pen so we have access to the old pen and plenty of scrap wood to expand as needed. I'm glad to hear that I can expect to move them into the garage after about a week, the old pen should be plenty large enough. I'd like to clarify, when you say a week are you estimating the time until the Pekin's outgrow the small brooder or when I can safely keep them in the garage with heat lamps? Hoping you mean the latter. If not, I will start redesigning a larger indoor brooder tomorrow.
Ide argue that heat lamps are great, and mabye even the best and most cost effective way to warm baby birds, But other heat sources work best for other people
i use a porcelin bulb thats garenteed shadder proof