Knighstar679
Crowing
They are probably wondering who those other ducks are in the glass. We once watched an adult roadrunner try to confront its own reflection in our sliding glass door. It was quite entertaining.
You have a nice, big space for your ducks, which is great, but with them still being young and the only ducks there, venturing out probably feels unsafe. Their main goal in life is survival and right now, that seems best assured by sticking close to their coop. The reality is that at this size, they are easy targets for any birds of prey in your area and staying close to cover is a good survival strategy. Consider whether there are other good cover options for them as they move out into your garden—especially on the way to and near your pond. Depending on the conditions in which they were kept before you got them, your garden may be much more unfamiliar to them than it seems.
I expect that your ducks will acclimate in time and also feel safer as they grow larger, though depending on the types of predators you have in your area, they will always need protection, especially from dusk to dawn.
I was just thinking they might be staring at the other ducks in the glass. When I had my Ryker in the house last year he used to poke his own reflection.
You could also but a bowl of something tasty out in the garden, like zucchini, peas, watermelon, lettuce or diced tomatoes to tempt them to venture into the garden to explore a bit.