What breed of ducks do you have?
I keep Indian Runner and Campbell ducks, both flightless domestic breeds. My Indian Runners and Campbells are free range all the time, but my home is in a remote rural area and the property is fully enclosed with fairly high cyclone fencing. There are no cats in the vicinity and local farm dogs and dingos cannot get in. Main predators in the district are snakes and birds of prey. I keep ducklings in a roofed enclosure (chicken wire roof with a section covered in tent material for weather protection - I'm in the tropics) until they are big enough to venture out and are too big and heavy for an owl or kite to pick up. In my vicinity they would be more likely to be taken by a python at night with no means of escape if housed in a coop. Being free range they can, and do, run away from snakes. (As do I!)
My only experience with ducks with flying ability were Muscovies. They were too agile for me to catch and I only managed to clip the wings of two. If they can fly, they will. I had the unfortunate experience of trying to keep them on the property. With all the grass, bushes, pond and food provided, everything a duck could want, the cane field across the road must have just looked bigger and juicier than all the food in the yard. They would perch on the fence, then fly off into the cane field. Unfortunately two were taken by farm dogs. They literally bit their tails off. The birds must have turned to run or fly away and the dog caught them by the tail, not just feathers, but flesh too, and they suffered horrible injuries from which they died. I gave the rest of the muscovy flock away to someone who could house them more securely than could I, and I now only keep flightless breeds.
Hope this provides you with a logical argument to put to your dad. It is always best to look at the pros and cons of your particular situation - local wildlife and district predators, whether an enclosure will provide protection - from what type of predator, or will it be a trap from which the predator can select its meal.
Here is my solution to an enclosure versus free range:
I do have a solid roofed shade house in which my ducks can rest if they choose. The entrance to which is permanently open but I dug out the soil and fibreglassed a pond right across the entrance. Predators usually will not cross water, especially if they do not know how deep it gets. The pond has chicken wire along both sides for about 60cm (2 ft) in width and going up to the height of the shade house roof. There is a garden arch at the entrance to the shade house, over the pond. Chicken wire is firmly attached from the arch to the shade house. The pond walls are vertical at these wired sides. To the front the pond levels out more shallowly so that the ducks can easily enter or leave the water, in the centre the pond is only about 30-60 cms deep (1-2ft) depending upon evaporation and how recently I have topped it up, just enough to deter a predator. In the centre at the back, just inside the duck/shade house, I have placed stones to give the ducks easy footing to get in and out at that end, but making it necessary for a predator to have to wade through the water to get to the entrance. I considered how far a cat (should one ever turn up in the district) would be able and willing to jump across water to reach the stones and I made the pond just a little too wide for that. The wire at the sides is not tightly fastened to posts or anything on the garden side of the pond, so anything climbing would cause the wire to swing down upon itself and either dump the predator on the ground or in shallow water, thereby frightening it away. The wire is not firm enough for a predator (other than a snake) to climb it and jump into the duck/shade house. The pond allows the ducks to run for cover across the water and into the shade house, or run from the shade house across the water to escape, whichever they need to do. I usually feed the ducks inside the shade house so that they associate it as their little house. There is a narrow door to the side of the pond that opens and closes so that I don't have to wade through the pond to get in or out of the shade house myself. The shade house was already on the property when we moved in. I simply converted it to the duck house.
Here's a picture, hope the link works, if not, paste the hyperlink into your browser.
and also I need you guys to scare him into penning them up at night. There is no way I am going to let them roam around at night. That's crazy to me.
