Chickens and Ducks
There are two types of birds you can own in Harvest Moon DS. You can raise chickens and you can raise ducks. Both foul will live in the poultry barns you can hire Gotz to build. Before you can buy ducks you'll need to have the Duck Pond built as well.
Each poultry barn can hold any combination of ducks and chickens, as long as you only have 4 birds for each barn. You can only have 7 barns total, which includes the barns you have built for your cows and sheep.
To buy chickens and ducks you need to call Popuri on your telephone. She sells chickens for 1500 G a piece and ducks for 2000 G a piece. Popuri also sells Bird Feed and she will buy birds from you. There is no way to produce your own Bird Feed for feeding your poultry when they are inside so make sure you're purchased plenty of feed from her.
A chicken will lay an egg every day (as long as it is happy) but a duck will only lay every 2 days. Duck eggs sell for a little bit more than chicken eggs but you'll earn more profit overall if you just stick with chickens. You can convert the eggs into Mayo by using the Mayonnaise Maker but the sell price is the same no matter what type of egg you used.
You can hatch new birds once you have purchased 1 of each type. Just take any size egg and place it in the straw bin inside of the poultry barn. It only takes 3 days for a new bird to be hatched and then another week before it turns into an adult. The growth times for chickens and ducks are the same.
The more hearts a bird has, the larger egg it can lay. You can increase your affection with your animal by leaving it outside, picking it up and down, and by using the Touch Glove to pet your bird. If you use the Touch Glove you can reach a Red Heart in the petting mini game with a score of 9000 with a chicken, and 6000 with a duck.