Those ducks are awesome. I'd be scared they'd fly away.
They can fly away, there's nothing stopping them. However they dont even venture to the end of the garden. They're very timid creatures. They've got their pond - which they love, regular food and shelter - and dried worms. They're happy.
The only time they 'fly' is first thing in the morning when I let them out their hutch. They run round out their enclosure and fly down the garden to our house as they know they'll get some worms there.
My dogs have a dog flap, so go out in the garden whenever they like. They get on fine with the ducks. In fact, the ducks are very territorial about their patch and they see the dogs off. Botox usually ignores them, but they give it a go.
I originally got three of them as little chicks and they were familiarised with the dogs straight away, but sadly one died in the first week. The other two grew up and became really happy and confident in their surroundings. I could stroke them and pick the white one up without too much fuss - and I was getting an egg a day from them.
However about a month ago we had a fox attack. I lost one duck and the white one was badly hurt. We didn't think she'd pull thorough, but after a few days she hadn't died, but was clearly not herself and lonely - so fortunately we sourced another duck to keep her company. The mallard coloured one is new so is not used to us. But having him around has perked the white one up again. She's not laying eggs yet, but - as you can see form the photo - is now eating from our hands and venturing out into the garden again.
Oh and if anyone is thinking of getting ducks as a pet - they are a LOT of work. I have to clean the pond pump out every night (ie clean poo out of the filter by hand) and they need cleaning out and feeding daily! They poo so much its unbelievable!