It depends on what the costume is made of, the degree of coverage of the costume and the environment in which it is worn. A costume made of fake fur that cover the body entirely will be a lot warmer than a costume made of tulle that involves a skirt over a leotard. It depends on whether the costume is to be work indoors or out, and what the weather is like, etc.
A duck costume would be a unique and creative choice. To make it even more unique stay away from character ducks, such as Daisy Duck or Daffy Duck. A home made duck costume would be the best way to assure that your costume is as unique as you.
If you are looking information on how to make your own duck costume for a toddler, the best site for your question on holidays.thefuntimesguide.com/.../homemade_halloween_costume
Besides rubber duckies, some other popular duck characters often featured in costumes are Daffy Duck, Donald Duck, Scrooge McDuck, and Daisy Duck. Another popular duck costume character (especially for Oregon residents and fans) is that of the Oregon Duck's mascot. The Oregon Duck's mascot wears a green and yellow costume, with a green and yellow beanie cap.
Costumecraze.com is a wonderful resource for all of your Halloween costume needs. If you do not find what you are looking for there, you can try amazon.com or ebay.com. Each of these places have many different duck costumes for your daughter.
Foghorn Leghorn
Grit, spit and a whole lot of duck tape.
I think the Kitana costume (from Mortal Kombat) is the hottest costume. The boots, the outfit, and the hood are so hot!
He must be in that thick costume...
Hot Topic, they sell a lot of Gir accessories, hoodies, and costume sets.
get a purple shirt, white tutu and a big pink hairbow.
Family Fun Magazine offers some great Halloween costume ideas. They offer individual costume ideas or ideas you can use for the whole family! http://familyfun.go.com/crafts/ducks-662521/
You could find an Indian costume at www.partycity.com, under the costume section. In addition, you could also find an indian costume at www.buycostumes.com.