I have eleven chickens in my 10m x 10m back garden. We do a paddock shift system with them, moving them to a different section once a week; we have four sections during the summer, and allow them two more in winter (the vegetable beds). Each paddock section has established perennials, both edible and ornamental, and all but the veg beds have a bit of lawn.
I use moveable chicken wire and metal posts to keep them contained in their paddocks, and the whole back garden is completely fenced and pretty much chicken proof; I keep their wings clipped too. We also have no predators big enough to take on a chicken: no foxes, no eagles. Because we have no predators, we can go away and leave them on their own for a few days at a time, so long as they have plenty of food and
water.
They are pretty content, and enjoy foraging for bugs and greens; they get very excited when they see us come out with the mallet: it means it's time to move to a new paddock section! We generally buy about 50kg of feed per month; we buy (the more expensive) non-GMO feed. At the moment, we're getting only about four eggs per day, so it's not exactly cost effective in winter; in summer we have to buy their feed less often and we get 8-10 eggs a day. We also buy a bale of
straw for their coop a couple times a year.
There are other benefits of chickens besides the eggs: they produce fantastic fertiliser, they eat weeds and pests, and they are fun to watch and interact with. My garden soil has really improved since getting chickens four years ago, and I have no weeds in my lawn any more. We like to sit outside in summer and watch "chicken tv." One of our hens loves to sit on my husband's lap and have a nice cuddle.
But chickens can also wreak havoc in the garden with their scratching and pecking. Just this week mine broke out of their paddock and ate all the leaves off my spring cabbage and broccoli! And there have been times when they scratched up whole beds of new seedlings, or even established plants. However, last year I had a terrible growing year for vegetables--nearly everything was destroyed by a plague of slugs--yet I still had a harvest of food from my garden every day, in the form of eggs.
In conclusion
in my
experience chickens are very doable in a small garden. The benefits outweigh the disadvantages, in my opinion. I think the biggest concern in keeping them in a small space is to make sure they are well fenced, protected from predators, and provided with enough space to meet their needs.