And some of that is true. Sort of. A chicken does love the garden. She loves the weeds and the worms and the slugs. She leaves hearty deposits of natural fertilizer behind her. And all of that is great.
The problem, however, is that she also loves the loose dirt to carry out her dust bath ritual, hollowing out bird-sized holes in your garden (while flinging your precious dirt everywhere), mowing over tender plants, and generally not caring at all that you've spent your time and energy in cultivating your beautiful plants.
Chickens in the garden do eat those nasty bugs. But they love the fresh fruit of the vine just as much. They're not going to let a nice, juicy strawberry or cucumber or tomato go unnoticed. They're going to feast to their hearts content.
How Does Garden and Chicken Co-Exist?
One way to deal with chickens in the garden is to fence off the area you don't want re-arranged or ruined by your birds.
Another way is to allow the chickens in BEFORE you plant your garden, to eat your weeds and deposit their natural fertilizer (poo) to your dirt. Then kick them out and plant your crop, protecting it from them later.
Some people construct their coop with two large chicken runs. They allow the girls access to one of them one year and plant in the other, and then switch it around. This benefits everyone. First, the chickens get a great place to graze and fertilize, and your garden space rests every other year while you grow on the other side.
This kind of set up isn't always possible for the urban chicken farmer, but it might be something to consider on a smaller scale.
Others allow their chickens in the garden in very limited, highly supervised ways. They let them in to eat bugs, but take them out before they get to carried away and start eating or destroying the plants. This works if you have the time for such intensive babysitting, but it's not for everyone.
To keep my chickens out of the gardens, I constructed a higher fence separating the front from the back yard. Where they used to fly over the fence and tear up the gardens in tech front yard, now they're relegated to the backyard only. A cheaper solution, however, would have been to clip their wings so they couldn't get over the fence that already separated the front from the back.
Regardless of the solution you land on, know that left unchecked, your chickens will most likely destroy your gardens. Some sort of planning up front will allow them to peacefully live together.