If you are unsure you will keep chickens in the long term, you could get a cheap coop to start with. Otherwise buy or make something that will last many years, e.g. . A coop with 1.4 metre sides (2 sqm of floor) is big enough for 5-6 chickens (0.33 sqm per bird)  (regulations allow hens to be kept at much higher densities—0.06 sqm per bird—but this commercial-type density is hardly recommended for your backyard chooks). Adding more space in the form of a mezzanine is valuable because it provides a three dimensional layout and environmental enrichment. It can be about 1.0 metre from the floor and run along the back. Without a stair-board it should be lower at about 0.7 metres. The chickens enjoy spending time there and will sleep there for the night. It is a frame made with 70 × 35 studs with Structaflor as base (therefore 70 mm deep), and also has a board at the front for the hens to roost on. It sits on the wall studs and can be lifted out if required. During part of the day I let the chickens roam in the backyard. However, chickens are destructive to a garden so if this is a problem you need to confine them to a run . This should have at least the same floor space as the coop. Design the coop so that the food, water and nest boxes dont take up valuable internal space and cant be soiled. The hens generally lay in the same nest box, therefore having one larger nest box, rather than two or more smaller ones, allows for communal laying and a shorter queue.
Litter should be used on the floor of the coop. Pine shavings can be used for a substrate, but a better product is Mini-Hemp (Ozhemp) which is more absorbent and mixes better with the poop. It is preferable to have a wood floor, e.g. Structaflor, because a dirt floor provides a route for vermin and can get damp. To start a deep-litter system, add about 5 cm of shavings/hemp to the floor. Then every day mix the shavings/hemp and incoming poop together with a 3-pronged cultivator. When the shavings/hemp and poop are in approximately equal amounts start adding new shavings/hemp to maintain the approximate 1:1 ratio. Most days give the whole thing a quick turn using the cultivator. With time the poop dries out and crumbles while the shavings/hemp act as a substrate. After several weeks the accumulating litter reaches the desired state: a slightly moist absorbent medium that quickly dries out new poop as it comes along. Indeed, its virtually impossible to see any fresh poop on the litter because of the speed of incorporation. Add new shavings/hemp as required, about every 2 weeks or so. This system is virtually no work except for the quick daily turn with the cultivator, and no smell! Cladding the first 20 cm or more of the coop from the floor with plywood will help contain the deep-litter as it builds in depth. Over one year it can get quite deep, up to 30 cm or more, after which it can be removed—now think compost—and restarted. Depending on how deep you can go, the depth can be lowered by taking some out at any time. I clean and add fresh sawdust to the mezzanine once per week as deep-litter is not practical in this location.
Broody hen management
A broody or clucky hen is easy to recognize; it wont get off the eggs! When this happens the hen needs to be isolated for 2-3 days until it gets over it. A small cage is useful for this purpose . Any add-on lighting will need to be applied to this small cage to ensure the hen will resume laying after its broody spell. Hybrid hens rarely go broody.
At least for crossbreeds, to maintain a steady supply of eggs its best to replace the hens after two seasons of laying, when they are about two years old. For social harmony replace them all at the same time. Bringing in new point-of-lay hens while you have older stock can be done but is best avoided if possible. The older hens will bully the younger ones on introduction, and this can be severe. If your older hens are particularly aggressive it can take a month or more for things to settle down. Don't introduce a single hen because it will be the focus of all the aggression—bring in at least two so they can share the brunt.
The Melbourne Scorchers
In Melbourne we get those scorchers hitting the upper thirties into the forties. Temperatures above 33°C are tough on the hens . One reason my coop is larger and tall is because it doesnt allow heat build-up and remains at ambient. Also, on the front overhanging roofline I hang a bamboo blind or shade-cloth to shield the morning sun; this has the added benefit of blocking night-light from the neighbours. On a really hot day the hens will seek refuge and could make for the coop because they see it as their safe haven. However, if the coop is small and in the sun, it becomes an oven and the hens die from the heat. So on those very hot days keep the hens outside so they can find some breeze and shade under a shrub, and ensure there is cool water (tap temperature) and food in the immediate vicinity. Provide the water in a large bowl to help it stay cool, and replace if it warms up. Immersing a frozen cool pack in the water will keep it cool for longer.
If you set up the coop with a high capacity feeder and drinker on a permanent basis, then when you go away merely top them up and alls well. You can get a Drinker Drum Kit from Bellsouth. There are various configurations but the 20 L tank is ideal and nipples are useful because they stay clean. Alternatively there is the BEC 75 drinker also from Bellsouth—it must be hung to work. Even if there is enough food and water to last the duration, ensure a neighbour or friend checks the coop on a regular basis to make sure all is in order.
There are several ways euthanasia is performed, including (1) cervical dislocation/neck-breaking [6,7,8], (2) captive-bolt , e.g. with the Stunning Apparatus for small animals (Friedrich Dick, Germany)—dubbed the Ballista, in conjunction with a killing cone, (3) Humane Poultry Killer (Morrigan Farm, Australia)—a neck-breaking device that mounts to a post, and (4) exposure to an oxygen-deprived (anoxic) environment using argon or nitrogen [8,9].
1. Building the poultry penthouse, Bolla G & Rees B (2007) NSW Department of Primary Industries
2. Housing and space requirements, Schultheis B (2011) University of Missouri Extension
3. The power of chook, Very Edible Gardens
4. Managing broody hens, Urban Food Garden
5. Understanding heat stress in layers (2016) Hy-Line Technical Library
6. Euthanasia for backyard birds, Petrik M (2017) mikethechickenvet
7. Is it okay for me to kill my own backyard hens? (2016) Royal Society for the Prevention of Cruelty to Animals, Australia
8. Practical guidelines for on-farm euthanasia of poultry (2016) Poultry Industry Council, Canada
9. Gas killing of chickens and turkeys (2005) Humane Slaughter Association, UK