About this time every year, we open up the potager (kitchen garden) for a month-long bill and beak treatment. This helps some with slugs and insect pests as well as weeds, weed seeds, and out-of-season volunteer plants. It also stirs the sheet-composted layer throughout and adds manure.
To do this, we run a section of used welded-wire fence around from one corner to the other, near the house, in such a way that the birds invest the garden with mucking up our walkways. We still have access through a gate we have by the driveway, the usual use of which is to import bales of straw and wheelbarrow loads of grass clippings and straw.
We also set up a five-gallon bucket of water, as ducks can die of asphyxiation from mud-encrusted beaks if they can't snortle in water from time to time, and it's a long way back to the barn from here.
When everything is ready, the gate from the garden to the far end of the "chicken moat" is thrown open. The waterfowl and the "wild bunch" chickens (Australorps) can be counted on to find this expansive opportunity first thing in the morning. The more sedate Araucanas and the rooster, however, must be driven at least once or they'll miss the whole show.
Here is a crude drawing of the sort of thing we're trying to do, though it does not represent our actual layout. The homestead (or least the part of it on the house's side of the creek) is surrounded at the perimeter by a tall deer fence, on which we are encouraging blackberries, grapes and such. Ten to twenty feet in is the poultry fence, forming in effect a moat -- the birds' pasture is the outer ring of the property. This keeps them active, as they have a large enough territory but it's long and narrow. Our home, yard, and garden have the "interior lines" -- thus we don't have to spend all our time thinking about chicken poop underfoot or tracking into the house.
The round things inside the chicken moat are the majority of the orchard trees. Apples and such that drop and are not retrieved by us are the traditional transition zone for some fruit pests -- but the birds get them, as well as the fruit. The birds also interdict slugs and snails that are migrating toward the garden. Those that get past -- well, we hope the birds can find them in November and December, when they are our guests in the inner sanctum.