What a correctly-set brooder looks like
Lamp suspended at minimum 15 inches above the litter via chain (never the cord), thermometer at chick level reading 90–95°F in week 1, and chicks distributed across the floor. Piled directly under the lamp means too cold; pressed against the walls means too hot.
The temperature schedule
Start chicks at 90–95°F at chick level under the heat source, drop temperature 5°F per week through week 6. Temperature is measured 2 inches off the floor under the edge of the heat source — not at the lamp face, not at adult head height, not in the ambient room.
| Week of life | Target at chick level | What you should see |
|---|---|---|
| Week 1 | 90–95°F | Chicks distributed across brooder, not piling under lamp |
| Week 2 | 85–90°F | First wing-feathers visible; still need full lamp coverage |
| Week 3 | 80–85°F | More feathered; spending more time at brooder edges |
| Week 4 | 75–80°F | Mostly feathered; lamp height progressively higher |
| Week 5 | 70–75°F | Fully feathered for many breeds; off lamp during day |
| Week 6 | 65–70°F | Most chicks ready to transition to coop in mild weather |
Why wattage is advisory, not the answer
The 250W heat lamp is the standard backyard-brooder bulb — generally sufficient for heating 80 chicks at a 50°F room temperature. Beyond that one anchor point, the wattage that hits the right chick-level temperature depends on enclosure size, lamp height, ambient drafts, bedding conductivity, and lamp geometry — none of which scale linearly with chick count.
The smaller-flock wattage brackets the calculator outputs (75W for under 10 chicks, 125W for under 20, 200W for under 40) are HatchMath methodology — practitioner brackets. They help you size a lamp purchase; the thermometer + chick behavior tell you whether the choice actually works for your specific setup.
The actual lever is lamp height. Run a minimum of 15 inches from the litter, with adjustment up to 24 inches to reduce heat output — that 9-inch range corresponds to roughly 10–15°F of chick-level temperature change. Enough to step a brooder through weeks 1–6 with the same bulb, just by raising the lamp 1–2 inches per week. Buy the right wattage in week 1 and keep it.
Brooder plate vs heat lamp — when each one wins
- Brooder plate (Brinsea EcoGlow, Premier 1).30–60W contact-heat panel. Chicks self-regulate by walking under it when cold. Substantially safer (no fire risk from infrared bulb), substantially lower power draw. Works for flocks up to roughly 25 chicks in moderate ambient temperatures. Trade-off: doesn't warm the air, only the chicks under the panel — won't pull a 50°F garage up to chick-survivable temperatures.
- Heat lamp (250W infrared). Air-warming, full brooder coverage, scales to large flocks in cold rooms. Real fire risk — requires the safety checklist above. The default for sub-50°F brooder rooms or flocks above 25 chicks.
- Heat lamp + brooder plate (combined setup). Some keepers run a heat lamp for ambient warming with a brooder plate as a self-regulating contact zone. Belt-and-suspenders for cold-room brooders or larger flocks where you want both redundancy and stress-reduction.
Frequently asked
Why does the calculator lead with temperature instead of wattage?
Because heat-lamp output does not scale cleanly by chick count alone — enclosure size, mounting distance, ambient drafts, bedding type, and lamp geometry dominate the actual chick-level temperature. The right answer is a temperature schedule (90–95°F week 1, drop ~5°F per week), not a wattage formula. The thermometer reading at chick level plus chick behavior are the only signals that confirm the brooder is right. Wattage is presented as an advisory starting range to help size a lamp purchase, not as the answer.
What if my thermometer reads outside the target range?
Adjust lamp HEIGHT first, not wattage. The bulb is sold at fixed wattage, but you can tune chick-level temperature by ~5–10°F just by raising or lowering the lamp 2–4 inches. Start with the bulb 18–20 inches above the brooder floor — 15 inches is the published minimum from litter. If the thermometer reads too high after lowering, raise the lamp. If too low after raising the lamp to its maximum height for your setup, swap to a higher-wattage bulb or add a second smaller lamp rather than pushing one giant bulb.
Is a brooder plate safer than a heat lamp? Should I just use that?
Brooder plates (Brinsea EcoGlow, Premier 1) are substantially safer than heat lamps — they use 30–60W (vs 250W for a heat lamp), produce contact heat only (no fire-risk infrared bulb), and chicks self-regulate by walking under them when cold. The trade-off: brooder plates work for chicks under the panel, not for the whole brooder enclosure, and they don't warm the air. For small flocks (under 25 chicks) in moderate ambient temperatures (60°F+), a brooder plate is the safer default. For large flocks or cold-room brooders (sub-50°F garage in winter), a heat lamp may still be required to bring ambient temperature into the chick-survivable range.
How do I know my heat lamp is mounted safely?
Five conditions, all required: (1) Suspended at minimum 15 inches above the litter using chain or wire — never the electric cord. (2) Two independent attachment points — chain plus a secondary clamp, or hook-and-eye plus a backup. The single clamp that comes with most heat lamps fails. (3) GFCI-protected outlet at the wall. (4) At least 12 inches of clearance from bedding, walls, curtains, or any flammable surface. (5) Bulb and socket undamaged — replace immediately if cracked, never duct-tape repairs. Heat-lamp fires kill chicks AND burn down brooders, garages, and entire houses every year. Confirm all five before plugging in.
Why does the calculator say red bulb instead of white?
Red infrared bulbs are the default for chick brooding because the shifted spectrum reduces stress and feather-pecking behavior in close-quartered chicks. Red also makes blood-tinged injuries less visible to other chicks, breaking the pecking-cascade that can occur in tightly-packed brooders. White bulbs work and chicks tolerate them — you'll just see slightly more stress behavior and slightly higher pecking risk. If red isn't available, white is fine; if both are available, red is the default.
Can I use a regular incandescent bulb instead of an infrared heat lamp?
No. Standard incandescent bulbs at high wattage (60–100W) don't produce enough heat to warm a brooder to 90–95°F at chick level except in tiny enclosures, and they're rated for room lighting, not sustained 24/7 heat output near combustibles. The 250W infrared heat lamp is engineered for brooder duty — higher heat output, sealed envelope, designed to run 24 hours a day. Don't substitute. The very small wattage savings aren't worth the fire risk increase or the chick-temperature gap.
Related
- Coop ventilation calculator →
- Coop size + run space calculator →
- Feed amount calculator →
- Methodology + sources →
- About HatchMath →
- Editorial policy →
By Jimmy L Wu. Temperature schedule, 250W/80-chick scenario, and 15-inch-minimum-from-litter suspension rule anchored to UMN Extension. Smaller-flock wattage brackets (75W ≤10 chicks, 125W ≤20 chicks, 200W ≤40 chicks) are HatchMath methodology. Engine logic in lib/poultry/brooder.ts. Not veterinary advice — for sick chicks or any animal-health emergency, consult an avian or livestock veterinarian, or your county Cooperative Extension office.