Alright here goes...
First off I would check out the sticky on raising ducklings. How many ducks are you planning on getting? Are you planning on letting them free range or are you going to keep them penned?
As ducklings, they eat unmedicated chick starter feed until they reach 8 weeks. At 8 weeks, they eat unmedicated chick grower feed until they reach 16 weeks. After 17 weeks they eat chicken layer feed if they are girls, and if they are boys they eat game bird feed.
Their house should be off the ground. You should use either pine shavings or straw for the bottom. Ducks are unlike chickens in that they roost, so you don't need any perches or elevated areas in the duck house. The minimum size of the house is 2 square feet per duck. The house should be ventilated, you can literally put tiny holes in the sides of the house or make a closable window. I built my house pretty basically. I nailed four giant wooden planks together, make a door and a window. The roof is slanted towards the back of the house. I added wooden planks for support inside the house in various locations. I can post pics tomorrow.
For the pen, the most important thing is that it has to be absolutely predator proof. I recently had a predator break into my duck pen and killed one of my ducks

. I had to make serious changes. So first, the pen should be about 4 or 5 feet tall. Mallards do fly, but you can trim their flight feathers so they are not able to fly. To make it predator proof, you want strong fencing, strong netting to put on top, a door to both the pen and house with a couple latches on each. You should buy a bunch of concrete slabs to place around the outside of the whole entire pen to prevent predators from digging in. Also, to keep away hawks you can buy predator tape off
amazon. Its reflective and makes a noise when wind hits it.
For a pond, use your judgment on the size. It depends on how many ducks you are getting. But make sure you are able to clean/ empty out the pond every week or so. There are also plants that can help clean the pond.
For ducklings, they can start to permanently live outside when they are a month old and the weather is 70 or above. Anything lower, and you should wait until they get their feathers in, or you can take them out for short visits outside if the temp is around 50 or 60 and the ducklings are six weeks old or older. Ducks usually have their feathers in around 8 weeks old. Whatever you do, make sure the little ducklings do not get a chill.
Mallards make very good mothers.
If you free range your ducks and they can forage, they won't need as much food as ducks who are not allowed to forage. I would watch how much food your ducks eat in a day when they are full grown, and adjust the amount of food you give them so that they finish it by the end of the day. Ducklings should have food available 24/7 until they reach 8 weeks old.
Good luck and have fun with the ducks!
