ReferenceGlossary

Backyard chicken glossary

Plain-language definitions for the terms that come up in backyard chicken keeping. Cross-linked into the calculators and guides that use each one. Add to bookmark and reference while reading the rest of the site.

Bantam: A miniature chicken breed (true bantams 1–2 lb, ~half the size of a standard layer). Bantams need ~2 sq ft indoors and 4 sq ft outdoors per bird, vs 4 + 8 sq ft for standards.
Broody: A hen sitting on eggs to incubate them. Broodies stop laying, get aggressive, and stay on the nest 21+ days. Some breeds (Silkie, Cochin) go broody readily; production breeds (Leghorn, Sex-Link) almost never do.
Candling: Holding an egg up to a bright light to see what's inside. Used during incubation at days 7, 14, 18 to check for embryo development, blood vessels, and air cell. Bright LED flashlight or dedicated candler. Incubation guide →
Chick starter: Feed for chicks 0–8 weeks. ≥18% crude protein, low calcium, often medicated with amprolium for coccidiosis prevention. Switch to grower at 8 weeks. Feed types →
Coccidiosis: Parasitic intestinal disease that kills chicks rapidly. Symptoms: lethargy, bloody droppings, hunched posture. Prevention: medicated chick starter (amprolium) OR coccidiosis vaccination at hatchery — not both.
Comb: The fleshy red crest on top of a chicken's head. Single combs (Leghorn, Plymouth Rock) lose tissue to frostbite faster than rose combs (Wyandotte, Buckeye). Comb damage signals moisture problems in the coop, not pure cold.
Deep litter: Bedding system where shavings are added on top of soiled bedding rather than scraped out — building a 6–10 inch stratified layer over the season. Decomposition generates mild warmth and breaks down ammonia. Requires adequate ventilation; clean out fully each spring. Winter ventilation →
Dust bath: Chickens dig shallow holes in dry dirt or sand and roll in them — strips parasites, conditions feathers, oils skin. Provide 1+ sq ft of dry loose substrate (sand, dry dirt, wood ash mix) in the run; chickens self-organize.
Eggbound: An egg stuck in the oviduct, unable to pass. Hen sits puffed and lethargic, may strain visibly. Treatment: warm bath (15 min), gentle abdominal massage, calcium supplement. If 24+ hours without resolution, see a vet — eggbound hens die without intervention.
Eyebrow vent: A small rectangular vent cut high on a coop's gable end, just under the eave. Standard DIY ventilation retrofit; 4×12-inch eyebrow vents covered with ¼-inch hardware cloth give ~0.3 sq ft of high-vent area each. Vent ideas →
Fertile egg: An egg that contains a developing embryo, possible only when a rooster has mated with the hen. Hens lay regardless of rooster presence; without a rooster all eggs are infertile (and edible) by default.
Free range: Letting chickens roam outside the coop and run during daytime hours. Reduces commercial feed intake 10–30%, improves welfare, increases predation risk. Most-of-daylight free-ranging requires lower predator pressure or active supervision.
Frostbite: Tissue damage from cold — most commonly to combs and wattles. The cause is rarely temperature alone; it's moisture-on-tissue at sub-freezing temps. Sealed coops with high humidity cause more frostbite than dry cold coops, even at much warmer temperatures.
Grit: Small hard particles (granite, oyster shell) chickens swallow to grind food in the gizzard. Required once chickens eat anything besides ground-fine starter feed. Chick grit (small) for chicks; adult grit (coarser) for layers. Offered free-choice in a separate dish.
Grower feed: Pullet feed (8–18 weeks). ~16% protein, no added calcium. Step-down from chick starter; precedes layer feed at point of lay. Some keepers run starter → all-flock → layer instead, skipping grower entirely.
Hardware cloth: Galvanized welded-wire mesh used for predator-rated openings. ¼-inch (6mm) excludes raccoons, weasels, mink, rats, snakes. Don't use chicken wire as substitute — predators defeat chicken wire easily. Predator-proofing →
Hen: An adult female chicken. Layers (in production) are typically 18+ weeks. Compare to pullet (immature female) and rooster (adult male).
High vent: Ventilation opening near the roof peak — above roost height. Exit path for warm humid air rising off the birds. Should never be sealed in winter; closing high vents traps moisture and causes condensation/frostbite.
Layer feed: Complete ration for active layers (18+ weeks). 16–18% protein, 3.5–4.5% calcium added for shell production. Don't feed to chicks or pullets — excess calcium damages developing kidneys. Best layer feed →
Layer rate: Eggs per hen per year. Production breeds (Sex-Links, Leghorns) lay 250–280/year peak; heritage dual-purpose breeds (Plymouth Rock, Wyandotte) 200–240; ornamental breeds (Silkie, Cochin) 100–150. Lay rate drops 50%+ during annual molt and in winter shortened daylight.
Lockdown: The final 3 days of incubation (days 18–21 for chicken eggs) when the incubator is sealed, humidity raised to 70%, eggs stop being turned, and you don't open the lid. Chicks pip and hatch during lockdown. Incubation guide →
Low intake: Ventilation opening at floor level — supplies fresh cool replacement air for whatever leaves the high vent. Place on the windward wall, behind a 12-inch solid kickplate so wind doesn't blast across the floor at perch level.
Mash: Fresh-ground feed in meal form (vs pellets or crumble). Highest waste of the three formats; best palatability and easiest to ferment. Most backyard keepers use pellets instead unless specifically running fermented mash.
Mealworm: Larval form of darkling beetle — high-protein chicken treat (~50% protein dry weight). Use sparingly (≤10% of daily intake); over-feeding mealworms throws off the layer-feed nutritional balance.
Molt: Annual feather replacement period, 6–12 weeks usually in fall. Hens stop laying, look bedraggled, eat less feed. Increase protein to ~20% during molt to support feather regrowth.
Nest box: An enclosed dark space where hens lay eggs. 1 box per 4 hens is the standard ratio. Internal or external boxes (cantilevered off the back wall, accessed from outside) both work; external preserves coop floor space.
Oyster shell: Crushed shell offered free-choice for laying hens — supplemental calcium for shell production. Hens self-regulate intake; non-laying birds (roosters, chicks) ignore it. Without it, layer egg shells progressively thin and the hen's bones lose density.
Pasty butt: Dried feces blocking a chick's vent. Common in week 1, fatal within 24 hours if not cleared. Treatment: warm damp washcloth, gentle wipe, vent open. Check chicks daily for signs.
Pecking order: The dominance hierarchy in a flock. Established through pecking, posturing, and occasional fights. Top hen accesses food and water first; bottom hen last. Stable flocks resolve quickly; new birds entering an established flock face violence (see Integration).
Pellets: Extruded compressed feed format. Lowest waste, easiest storage, no dust. Default format for adult layer feed; suitable for pullets and most chicks (small pellets). Compare to crumble (broken pellets) and mash (fresh-ground).
Pip: The first crack a chick makes in the eggshell during hatching, around day 21. Chick uses an egg tooth (small bump on the beak) to break through. After internal pip (chick breaks into the air cell), external pip (visible crack) follows within 6–24 hours.
Point of lay: The age at which a pullet starts laying eggs — typically 18–22 weeks. First eggs are small and irregularly shelled for the first 1–2 weeks; this is normal. Daylight hours and breed influence timing.
Pop door: The small chicken-sized door from the coop to the run. Closed at sunset, opened at sunrise — the basic predator-control routine. Automatic pop-doors with light or timer triggers automate it.
Pullet: An immature female chicken, 8 weeks to point of lay (~18–22 weeks). Eats grower feed (~16% protein, low calcium). Compare to chick (0–8 wks) and hen (laying adult).
Roost: The horizontal bar chickens sleep on. Standard: a flat 2×4 mounted with the wide side up, 18+ inches off the floor. Flat 2×4 lets birds settle feet-under-feathers; round dowels expose toes to ambient air, increasing frostbite risk in cold climates.
Roost length: 8–12 inches per bird on the bar. Heavy breeds toward the upper end. Total roost length is what governs how many birds can sleep comfortably; floor area sets the upper bound but roost length is the practical constraint at typical stocking.
Run: The fenced outdoor enclosure attached to the coop. 8–12 sq ft per bird in temperate climates, scaled up for hot/humid. Hardware-cloth-rated against predators, with a buried apron or 24-inch surface skirt to prevent digging.
Scratch grain: Cracked corn, milo, oats, wheat. Treat-grade nutrition (10–12% protein, no balanced amino acids, no calcium). Use as ≤15% of daily intake — never as primary feed; flocks fed primarily on scratch crash lay rates within a month.
Sex-link: A hybrid chicken bred so chicks can be sexed at hatch by color or feather pattern. Common production breed; brown sex-links lay 280+ brown eggs per year peak, red sex-links similar. Hardy, friendly, top backyard egg producer.
Stack effect: The physics of warm humid air rising and exiting through high openings while cool fresh air enters through low openings. Drives passive ventilation in coops without electricity. Requires high outlet AND low intake at different heights — same-height openings stall. Stack-effect ventilation →
Vent: (1) The single combined cloacal opening on a chicken — egg, urine, and feces all exit here. (2) An air opening in the coop wall for ventilation. Context disambiguates.
Vent gleet: Yeast infection of the vent area. Symptoms: matted feathers, white discharge, foul smell. Treatment: clean the area, apply antifungal cream, switch to high-quality probiotic feed. See a vet if persistent.
Wattle: The fleshy red flap hanging below a chicken's beak. Like the comb, susceptible to frostbite from sealed-coop moisture. Damaged wattle tips are an early warning sign of inadequate ventilation.

By Jimmy L Wu. Definitions reflect practitioner consensus across hatcheries, 4-H poultry programs, and Cooperative Extension Service publications. Where a term has multiple common meanings (e.g., “vent”), the most common backyard-keeper usage is given first. Not veterinary advice — for sick birds or any animal-health emergency, consult an avian or livestock veterinarian, or your county Cooperative Extension office.

Backyard chicken glossary

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