My books say that a good rule of thumb for a shelter for geese/ducks is 5/6 sq ft/duck and 10 to 15 sq ft/goose . . . but they also say that most geese and ducks do just fine after they are all feathered out with no shelter. Our three adult ducks are perfectly content with sleeping outdoors -- sometimes they'll sleep under our chicken house (the chicken house is built onto a trailer) but half the time they are in the open. As long as there is a shady spot for hot days they seem to be fine in the open. We are going to use a couple dog igloo things for nesting areas later when they lay . . . In the winter we are going to build a three sided windbreak with hay bales -- but I think the geese/ducks will probably be fine without it, except on really cold/windy nights. For a brooder house for ducklings/goslings, my references said 1/2 sq ft/duckling on the first week 3/4th sq ft 2nd week 1 sq ft by the third week ending at 2 1/2 sq ft by the 7th week For Goslings the same reference said 1/2 to 3/4 sq ft on the first week 1 to 1 1/2 sq ft on the second week keep increasing space each week until they go onto range. This book says they can go on range as early as 2 to 4 weeks, but I can't send mine out into our rainstorms until they are feathered on the back. On the other hand, my geese and ducks are extremely unhappy being shooed inside every night. They are 5 weeks and not completely feathered out on their lower backs, but definitely close. I think I'll put them out next week. And, to be perfectly honest, I didn't measure space for my 7 goslings and 11 ducklings . . . I used what I had and gave them more space as soon as they seemed crowded / unhappy . . . but I had a large 20 ft by 20 ft concrete block stall to work with . . . I hope this helps! I used Storey's Guide to Raising Poultry and Ducks and Geese in your Backyard by Rick and Gail Luttmann. The last book was fun to read - had a lot of humor, and good information. The Storey book was more dry and had less info but it more or less agreed with the other.