If you have enough room put the chicken coop in the center of the garden area and fence off 4 separate quarter areas, each with limited access to the coop and rotate the chickens each year you can have an almost self sustaining garden in just a few years. The chickens will eat the weeds, weed seeds and insects from that area and fertilize that area for next years green garden. Greens like high nitrogen and the chickens supply that. Next year move the chickens to the next over grown weedy area and let them do their stuff. You can now plant your regular summer garden in last years green area and the 4th year let that area go fallow or plant a cover crop. After a few years you have a chicken area, a greens area, a regular garden area and a fallow/cove crop area, each progressing the next year. This will eliminate weed problems, insect problems and add good organic fertilizer to your garden area. With a little supplemental liming and adding other micro nutrients to cover possible deficiencies the garden should take care of itself with the exception of harvesting.
