It sounds to me you are thinking of containing them similar to Game chickens/cocks. I STRONGLY advice AGAINST this. A few reasons why:
-It will leave sores on there leg which can easily turn to infection
-It will lead them to become overweight, they NEED space to roam
-And there is no point because Pekins can't fly
If you have true mallards, clip there wings. Its simpler and more humane. Just take sissors and cut through he wing feathers, they will bleed a little, but its not painful and there is no long lasting affect. If you choose to have them with full wings, they just need to molt and new full feathers will come in. Ducks need twice preferably three times the space chickens do, plus its prefered you have something for them to bath in (a kiddie pool works great). Ducks enjoy each others company so you want them together, though remember there should be a 1 drake(boy) to 3 hen (or more) ratio to keep the peace.
Oh hear are some general facts on ducks that might help:
- Ducks should have room to roam, roughly 2-3square feet per small duck and 3-5 square feet per large duck (Pekins for instance)
-They are messier then chickens, so change the bedding regulary to keep mold from growing.
-They should have a place to bathe, kiddie pools work great, but even letting them play in a flooded puddle often works great
-Ducks can eat pretty much any feed, but make sure its NOT medicated, to much medication will kill them
-They are fine to keep with other types of poultry, but the drakes will probably try to mate with any femal poultry, so keep that in mind