Metal Chicken Runs: How to Choose Size, Wire Gauge and Configuration

A metal chicken run is a practical, long-lasting choice for keepers who want a secure outdoor space for their flock without the ongoing maintenance that wood can demand. Whether you are setting up your first run or replacing something that has seen better days, the options can feel overwhelming if you are not sure what the key specifications actually mean. This guide breaks down everything you need to know: wire gauge, aperture size, run dimensions, height and whether you can extend later.

Why Choose Metal Over Wood for a Chicken Run?

Wood is a perfectly reasonable material for a chicken run, and a well-made wooden run will serve a flock well. But metal has specific advantages that make it the better choice for a lot of keepers, particularly those who want to set something up and leave it largely alone.

Galvanised steel does not rot. A wooden run will start to soften and degrade in the corners where it sits on the ground, and the mesh panels attached to the frame will start to lift and loosen as the wood shrinks and warps with changes in moisture. Metal framing maintains its shape. The joints stay tight and there are no gaps developing quietly over winter.

Hot-dipped galvanised steel is also straightforward to keep clean. You can pressure wash a metal run without worrying about the finish breaking down. That matters if you rotate or move the run, or if you are trying to keep the ground healthy by cleaning the structure regularly.

Fox resistance is another practical difference. A metal frame does not flex under pressure in the same way a tired wooden one might. The mesh is fixed to a rigid structure that stays rigid.

A hot-dipped galvanised run, properly installed, should outlast multiple wooden coops. The upfront cost is higher, but it is a long-term investment.

The honest summary: if you want low maintenance and permanence, metal is the better choice. If you are happy with an annual wood treatment routine and prefer the look of timber, a good wooden run is equally fine. The decision comes down to what suits you.

What Wire Gauge Should a Metal Chicken Run Have?

Wire gauge is one of those specifications that catches keepers out, because the numbering system works backwards from what you might expect.

A higher gauge number means thinner wire. A lower gauge number means thicker wire.

So 16g wire is heavier and stronger than 19g wire. Our metal runs are built using 19g galvanised wire as standard, with a 16g heavy-duty option available.

19g wire handles typical UK fox pressure well. It is the standard across most quality metal runs and is entirely appropriate for the vast majority of backyard flocks. If you are keeping hens in a normal suburban or rural setting and foxes are a regular nuisance but not an extreme problem, 19g does the job.

16g wire is worth considering if foxes are particularly persistent in your area, if you have had previous incidents with a determined animal, or if you have a significant investment in your flock, whether in financial terms or because you keep rare or valuable breeds. The heavier wire adds a meaningful step up in resistance to sustained pressure and repeated attempts at the mesh.

Both gauges use hot-dipped galvanised steel rather than electro-galvanised wire. Hot-dipped galvanising applies a thicker, more durable zinc coating that holds up better against the weather and against physical wear over time. For a structure that will sit outside year-round, it makes a real difference to longevity.

For a deeper look at the difference between wire types and grades, read our guide to chicken wire vs aviary wire.

What Aperture Size Do You Need for a Metal Chicken Run?

Aperture is the size of the gaps in the mesh, measured as each individual opening in the wire grid, and getting this right is one of the most important decisions when choosing a metal run because different aperture sizes do different jobs.

For fox exclusion, an aperture of 25mm or smaller is the standard recommendation. The mesh on our metal runs is 25mm aperture, which is correct for keeping foxes out. A fox cannot push its snout through a 25mm gap in a way that allows it to pull mesh apart. For a full overview of fox-proofing measures, see our fox-proofing guide.

For rat exclusion, 25mm aperture is not sufficient. Rats can pass through gaps of around 25mm with ease, and juvenile rats can get through even smaller gaps. To exclude rats, you need an aperture of 13mm or smaller. This is typically hardware cloth rather than standard aviary mesh.

This distinction trips up a lot of keepers. A metal run with 25mm aperture mesh keeps foxes out perfectly, but the apertures are too large to exclude rats. The two problems require different solutions.

If rats are an active issue, a buried hardware cloth skirt around the perimeter of the run at 13mm aperture is the additional step. This is laid horizontally on the ground and extends outward from the base of the run, then covered with soil or turf. Rats dig along the base of structures rather than straight down, so a horizontal skirt is more effective than simply burying vertical mesh. For more detail on managing rats around a chicken run, read our guide to rats and chickens.

How Do You Size a Metal Chicken Run for Your Flock?

The numbers given as welfare minimums for chicken run space are a starting point, not a target. The legal minimum in UK commercial settings is 4 square metres per hen for free-range outdoor access, but backyard flocks operate under different rules. What matters practically is that your hens have enough space to behave naturally, stay healthy and keep the ground in reasonable condition.

A run that looks generous on paper can feel much smaller once four or five hens are in it. Hens move, scratch and establish territories. Go bigger than you think you need.

A practical guide to run sizing based on flock size:

The reason recommended run area sits well above the minimum is straightforward: a run at the minimum quickly becomes bare, muddy ground. Hens scratch and pull up vegetation fast. Once the ground is bare, it stays bare and becomes unhygienic. A larger run stays in better condition longer, and hens in a well-sized run are less stressed and less likely to develop the boredom-related behaviours that come from being in a space that is too tight, such as feather pecking.

For more guidance on matching coop and run sizes to flock numbers, see our stocking density guide.

Should You Buy a Standalone Run or Attach It to an Existing Coop?

Not everyone buying a metal run needs it to come with a coop attached. Many keepers already have a wooden or plastic coop they are happy with and want a better, more secure run to go alongside it.

Most of our metal runs can be used either as standalone structures or alongside an existing coop. If you are attaching the run to a coop you already own, there are a couple of practical points to think about before you buy.

Pop hole position. The pop hole on your existing coop needs to align with an opening in the run. Check the height of the pop hole from the ground and confirm that the run panel can accommodate it cleanly. Some runs have a specific opening point built in; others are flexible enough to allow different connection points.

Height compatibility. If your existing coop has a raised floor with a ramp, the run needs enough clearance at the base to allow hens to enter and exit comfortably. A few centimetres of mismatch is usually manageable with a small ramp extension, but it is worth thinking about before the run arrives.

If you are setting up from scratch, buying a run and coop together as a matched system removes this complication entirely.

Is Walk-In Height Worth It for a Metal Chicken Run?

Metal chicken runs come in two broad height categories. Walk-in runs are full standing height, typically 180cm or above. Non-walk-in runs are lower profile, often 100–120cm, and designed so the keeper does not need to enter the run to manage the flock.

Both have a place, and the right choice depends on how you keep your hens.

Walk-in runs are more practical for daily egg collection and cleaning. You can move around the space upright, reach nest boxes and feeders without crouching, and spend time in the run comfortably. For keepers with larger flocks, or those who want to spend time with their birds, this makes a real difference over months and years. Walk-in height also makes it much easier to carry out maintenance tasks like replacing bedding, checking for health issues or clearing muddy ground.

Lower profile runs are cheaper, more compact, and take up less space in a garden. They suit small flocks where the coop is attached and the keeper does not need to go inside the run to collect eggs or fill feeders. If you have two or three hens with an attached coop and an external feeder and drinker, a lower profile run can work perfectly well day to day.

A simple way to decide: think about how often you will need to enter the run. If the answer is every day or close to it, walk-in height is worth the additional cost. If you can manage feeding, watering and egg collection from outside the run, a lower profile option is a reasonable choice.

Can You Extend a Metal Run Later?

Yes, in most cases. Modular metal runs are designed so that additional panels can be added to lengthen the run as your flock grows. This is one of the practical advantages of a metal frame over a fixed timber structure.

Before you buy, it is worth confirming that the specific run you are considering is extendable and that compatible extension panels are available. Not all metal run ranges are modular to the same degree. Some are designed with extension in mind from the outset and offer panel packs specifically for the purpose. Others are complete fixed structures.

If you are likely to add hens in the next year or two, this is a question worth asking before you buy rather than after. A run that can grow with your flock is a better long-term choice than one that leaves you replacing the whole structure when your flock expands.

A common pattern among backyard keepers is starting with three or four hens and adding more within 12 to 18 months. If you recognise yourself in that, buying a modular run and sizing it generously from the start will save you money and effort later.

Frequently Asked Questions

Are metal chicken runs fox-proof?

A well-built metal run with 19g or 16g galvanised mesh and 25mm or smaller aperture provides strong protection against foxes. No run is entirely proof against an extremely determined fox, but a properly constructed metal run with secure latching, buried or ground-pinned edges and no gaps at the join to the coop will defeat the vast majority of fox attacks. The critical weak points are the entry points, the base of the run where it meets the ground, and the connection between the run and the coop. For a full breakdown of fox-proofing measures, read our fox-proofing guide.

What gauge wire keeps rats out of a chicken run?

Standard 25mm aperture aviary mesh, whether 19g or 16g, keeps foxes out but not rats. To exclude rats, you need 13mm aperture hardware cloth. This is typically used as a buried perimeter skirt around the base of the run, extending outward horizontally by at least 30cm, rather than as the main run mesh. Rats dig along the base of structures to gain entry, so a horizontal buried skirt is more effective than vertical buried mesh. See our guide to rats and chickens for a full run-through of rat-proofing measures.

How big should a metal chicken run be for 6 chickens?

The minimum practical size for six hens is 6 square metres, but 12–18 square metres is a more realistic recommendation if you want hens that are comfortable and ground that stays in good condition. A run at the bare minimum for six hens will become bare and muddy within a matter of weeks. Hens scratch constantly and quickly strip vegetation. Going bigger than you think you need is almost always the right decision.

Can I attach a metal chicken run to a wooden coop?

Yes. Most metal runs can be used alongside an existing wooden or plastic coop. The key practical points to check before buying are the position and height of the pop hole on your existing coop and whether the run panel has a suitable opening in the right place. If you are attaching the run to a raised coop with a ramp, make sure there is adequate clearance at the run base. In most cases these adjustments are straightforward, but it is easier to think through before the run arrives than after.

Browse Our Metal Chicken Runs

If you are ready to choose a metal run for your flock, you can browse our full range at the Metal Chicken Runs collection. Our runs are built with 38mm hot-dipped galvanised framing and are available in a range of sizes, with walk-in options for larger flocks and keepers who want full access. If you have a question about which run suits your setup, get in touch and we will help you work it out.