Standard size chickens require 4 sq ft of floor space, about 1 linear ft of roost space and as close to 1 sq ft of PERMANENTLY open and predator proofed ventilation per bird as possible. One nest box per 4-5 birds will suffice with 2 boxes minimum if you only have 4-5 birds.
Their outdoor run area should be in a very well drained, DRY location with an area of full shade if possible. Having some or all of it protected by a pitched solid roof is ideal. The run should offer an additional 15 sq ft of space per bird.
There are a lot of people who will recommend 10 sq ft/bird as the minimum run size. But when you are looking at your flock of full grown chickens and lay out that amount of space for them you quickly realize it is not enough.
Having more space helps in so many ways.
It keeps the poop load per sq foot down to something the earth and some dry organic litter can manage.
It give the birds more personal space when they need it.
It provides space for enrichment like lots of different height roosting, pallets or boards or whatever leaned up against the run walls for hiding places as well as multiple feed and water locations.
Having more space also gives broody hens more room to maneuver within the flock to raise her chicks.
It also makes integration easier for non-broody raised chicks.
You need to have sturdy fencing. Chicken wire is not at all predator proof. You need 1/2" hardware cloth over 2x4 wire or chain link or another sturdy fence. Backing that up with well placed hot wires or poultry netting that is powered with a very punchy charger (10,000 volts/1.2 Joule output minimum) will be a very convincing deterrent indeed.
I use 1/2" hardware cloth to secure all ventilation and windows openings in my coop and cover the run walls with it. It is also extended out 18-24" across the ground and pinned down with heavy duty landscape staples to form a predator apron to keep out digging predators. My whole setup sits inside 1/3 acre enclosed with poultry netting with the above mentioned charger. In 8 years, not a single bird has been lost to a ground predator in this set up. I have seen fox, racoon, fishers and black bear in my yard and have heard coyote and bobcats. None mess with my chickens.
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