Just watch they don’t chill. I took mine out everyday for outside time and being around the other ducks they are pretty tough little things. Do you have a thermometer you can put in the heat cave so you can keep tabs on the temps? I started mine 2 days before mine arrived so I’d know how steady...
It looks good what are you going to use on the bottom of your brooder? I used a heat plate an my Runner ducklings spent more time on top than underneath.