Chickens wintered in the greenhouse
One structure doing three jobs — and one gas that decides whether it works.
What it is
The coop opens into the greenhouse, or the flock simply lives in it over winter. The birds add body heat and CO₂, scratch and till the beds, and eat overwintering pests.
The numbers
- All three effects are real: a chicken is roughly a 10-watt heater that also tills.
- But a chicken also produces a great deal of moisture and ammonia, and a sealed winter greenhouse concentrates both.
- Ammonia at 25 ppm is already damaging to birds' respiratory tracts — and the honest field test is that if you can smell it at your own head height, it's far too high at theirs.
Why it's here
The structure-doing-three-jobs idea is exactly the philosophy of this site, and when it's done right it genuinely works. It is also the single most common way people give their flock respiratory disease, so it gets a ◇ and a long catch.
The automation angle
You almost certainly already have a humidity sensor in the greenhouse. Watch it. Rising overnight humidity through December is the early warning, and it shows up weeks before anybody smells anything.
The catch
Ammonia and humidity. It works with properly managed deep bedding and real, deliberate ventilation — the kind you size on purpose, not the kind you get by cracking a door. Without that, you get frostbitten combs, sick birds, and plants with mildew. If you are not willing to run the ventilation in January, don't start.