Leghorns are lean, restless, excellent layers bred for a Mediterranean climate, and their winter weakness is written on their heads: a tall single comb and long wattles with a lot of exposed skin and very little feather cover. In a damp, closed-up coop that comb is the first thing frostbite finds. Leghorn shelter is therefore less about making the coop warm and more about making it dry and gently moving at the top, while the birds themselves sit out of any draft below.
Ventilation above, calm air at roost level
Openings high in the coop — under the eaves, at the ridge, on the sheltered side — should stay open all winter so moisture from breath and droppings leaves instead of condensing and settling back on combs overnight. What you are avoiding is a breeze at roost height: check on a windy night with a hand held where the birds sit. If feathers ruffle there, baffle that opening; if the air up high is still and the windows fog, open more at the top. A Leghorn tolerates a cold, dry night far better than a mild, wet one, and wrapping this breed's coop tight is the classic way owners cause the frostbite they were trying to prevent.
The roof must be genuinely watertight, because a slow drip onto litter undoes everything else. Deep, dry litter on the floor absorbs moisture and gives these active birds something to scratch through on days they choose to stay in.
Roosts built for a light bird with a big comb
Give Leghorns wide roost bars — the flat side of a broad board is ideal — so each hen sits with her feet flat and her breast feathers covering her toes completely. A narrow, round perch leaves toes curled and exposed, and toe frostbite in a light, flighty breed often goes unnoticed until a bird limps. Set roosts at a height these athletic birds can reach easily, but not so close to the roof that a hen's raised comb sits in the coldest, dampest layer of air or brushes a frosty ceiling. Leghorns roost high by instinct, so leave clear headroom above the top bar.
Space matters on the bar itself. A bird pushed to the end of the roost sits in colder air and cannot tuck in among the others, so provide more total roost length than the flock strictly needs.
Watching the comb, and keeping layers moving
Check combs on your morning round after hard nights. Pale or white tips are an early warning; dark purple or blackened, swollen tissue is established frostbite — do not rub it or apply anything greasy, keep the bird dry and eating, and get poultry or veterinary advice if the area swells, weeps, or the hen goes dull and off feed. Hens that stop laying in deep winter are often simply responding to short days and cold, but a Leghorn that also stops ranging, huddles fluffed on the floor, or isolates herself needs a closer look.
Leghorns stay active in cold weather and lay better for it, so keep the run usable — windbreak on the exposed side, dry ground cover where they scratch, and unfrozen water checked more than once on bitter days.
A flock routine split between several people only works when the comb checks, water rounds, and litter top-ups are written down in one place, which is what KinsLe Family Sharing does by keeping the Leghorns' profile and care notes the same for everyone in the household.