They will spend most of their time in a coop/run, but I will be letting the ducks out for a few hours a day to free range in the 1.5 acre yard. It is enclosed by a standard 4 foot high chain link fence. On one side is the neighbor with 2 chicken killing dogs that would gladly kill a duck that jumped into their yard. The other side is a 60 acre lake, in which I am sure the ducks would consider a better home than a coop inside a 1.5 acre yard and would never return. Will they be able to jump/fly over a standard 4 foot chain link fence? Or should I get a fatter breed such as Jumbo Pekin?