One year one space is a chicken run (chickens will pretty much clear out a smaller area in a couple of months) and the other area is a garden. While you let the chickens have the run of an area, they are eating out the insect larvae and eggs, spreading manure and scratching and shredding any scraps you throw in speeding up the process of composting. Chickens can make short work of a compost pile. At the end of the year when you begin to clear out your garden, you move the chickens over to that space and they begin to clear up the garden scrap and turn it into manure and preventing it from rotting and causing fungus and disease, they eat the adult insects which began to take hold on those plants and prevent them from growing in number and they scratch the now somewhat compacted soil and turn it a bit.
In the area the chickens have recently abandoned, you plant winter crops and start a winter green manure. allow the chickens to visit this area for a few days in the spring, before you till, and after spending a lot of time indoors over the winter they will happily and rapidly begin to eat some of the green manure, scratch it and and hunt insect. Then you return the chickens to their year two pen (the old garden) till new garden section and the remaining green manure under and begin the years planting.
Chickens can be kept, for the most part, inside a four foot high fence if you keep ONE of their wings trimmed. They cannot get any real height with one wing clipped because they cannot keep their balance.
A really cool idea for a fence is osage orange (edible and a natural insect repellant)or Siberian pea shrub (also edible and has been used in the past to feed chickens) as a living fence.
You have a good plan, please keep us informed of your progress