You can feed your ducklings duckling starter. I get mine from TSC, it is Dumor brand and has a little duckling and chick on the bag. I would definetly not put them in or raise them with your pheasants. Your flight pen sounds good, does it have netting on it?
There is no need to clip their hind toe if they are domestics, however if you got the eggs from the wild, I hope you understand that is illegal.
Yep,
That's what I was going to say too.
As long as they are over 3 generations form the wild, no permits are required for mallards. Under 3 gen. yes you do have to have it.
Also to your landscaping question, sure thats a great idea. I live in a low area myself , have a 12 acre swamp and a creek that runs threw the property. I always dug up stuff from around the swamp and put in the pens for them. Cattails, reed grasses, black willow trees, anything like that to make it more "natural" will go a long way for any of them.
Mallards even the wild strains will fall into that "do not put them in with any other species" class though, they will cross breed everything in the pen with them.
No do not mix them with ANY upland birds, not so much for the ducks sake, but the upland bird's. The mess waterfowl create can be very deadly bacteria wise to upland birds, especially game fowl like turkeys, partridge, grouse, pheasants and quail.
~Aubrey & Aimee~ 
JOIN THE D'ANVER CLUB OF AMERICA!
Breeders Specializing in 30+ colors quality D'Anver, 15+ colors Bantam Phoenix, Ohiki , 4 colors Bantam Sumatra, Imported lines of large fowl Phoenix, Longcrower , Cayuga Ducks, 10 colors Call Ducks. 25+ years experience with migratory waterfowl.
~Aubrey & Aimee~ 
JOIN THE D'ANVER CLUB OF AMERICA!
Breeders Specializing in 30+ colors quality D'Anver, 15+ colors Bantam Phoenix, Ohiki , 4 colors Bantam Sumatra, Imported lines of large fowl Phoenix, Longcrower , Cayuga Ducks, 10 colors Call Ducks. 25+ years experience with migratory waterfowl.


















Greatly appreciated.
lol. Just chop it right directly in half and get some mandarins or wood ducks for the other side, or both! i know those can be housed together. 

I need something in there to eat it though! My mandarins like to sit in the pond and pick at a couple plants I have right next to it. They never really do any damage, they just pick at it.



)