Just a heads up on this idea.
First,,, your flock may destroy your garden. There is a garden thread,,, a very active one BTW. and folks try their best to keep their chickens out.
Second point, an important one; Plants in the Nightshade family,,, the green portion of tomato, and potato plants are toxic to chickens. I'm sure ducks and geese as well. Red ripe tomato fruit poses no risk.
Best to free-range in the backyard lawn. They will pick their greens, (including dandelion) and any insects crawling in grass.
And last point about ducks,,, which you may already know about; When ducks drink, they need to dip their whole beak deep into water. Chickens can drink out of shallow containers.
During winter, if the water is freezing up,,, it does get a challenge for ducks.
Then come summer time. During extreme heat,, the water gets too warm. Chickens will not drink very warm water. They will dehydrate even though the water is right next to them.
Good to change their water frequently during such times.