Much of the information I’ve read on gardening with chickens puts it simply: don’t. Keep the chickens out of the garden because they can be so destructive. Although one corner of my flower bed has now become dedicated dust-bathing space, for the most part I have found that gardens and chickens can co-exist quite harmoniously.
You do want to keep your chickens out of the garden when your seedlings first appear, for obvious reasons. At that tender stage even a wayward hen foot could cause great damage. But once the plants have reached a few inches tall you should be able to allow the hens in.
There are two main issues with chickens in the garden. The first is dust bathing, the other is eating your plants. Although chickens can scratch pretty aggressively for bugs, it’s usually not deep enough to be an issue for mature plants. Plant eating is simple: it’s really hard for chickens to do any real or lasting damage. They are much more interested in bugs than veggies, so although they might peck at a leaf, they won’t chew it down to a nub like a goose would. Even a whole flock won’t cause any serious issues this way. There is even a positive side – they will rip out small weeds for you.
As for dust bathing, this can be fairly destructive. There’s nothing a chicken loves more than rolling in some fresh dirt on a hot day. The best dirt for bathing isn’t the packed stuff in your paths, it’s the loose soil near the plants. Be aware of where you chickens are bathing. Often they will have a favorite spot which they return to again and again, and will not bother other areas. You can surrender that spot to them if you’d like, and leave the soil empty and lose there. You can also make sure to check it every day, and replace any dirt that’s been pulled away from roots if you have a hardy plant growing in that area. My chicken’s favorite spot is the row of tomatoes, and I just push the dirt back every evening without any real damage to the plants. Because chickens are so predictable in their dust bathing preferences – loose, dry soil – it’s usually fairly easy to plan accordingly.
The positive side of chickens in your garden is clear: pest control. Chickens love nothing more than bugs. Although they will also eat plenty of earthworms and ladybugs, which are great for your plants, they do love some of the big villains in the garden. Chickens, and particularly guinea fowl, are experts at tick control. They will also eat potato beetles, slugs, squash bugs, various caterpillars, and the dreaded Japanese beetle. A flock foraging through your garden will help significantly, but if you get an infestation of a particular pest you can hand pick the bugs and then allow the hens to have them with their breakfast. They will eliminate them and appreciate the tasty treat.
The one pest I have not found chickens to be helpful with is the Tomato Hornworm. Unless it is an immature worm, even the chickens will hesitate to take on such a huge and ugly meal.