At Day 22, broilers enter Stage 4 (Rapid Growth & Density Management) weighing over 1.1kg. Metabolic heat production doubles every 10–12 days at this stage, requiring active air movement over bird backs rather than passive air exchange to prevent suffocating heat pockets.
Failure to remove bird-level heat immediately drops feed conversion efficiency and increases sudden death syndrome (flip-over) or pulmonary hypertension (ascites). Birds must feel an effective wind-chill temperature of 20–22°C.
•Relying solely on wall thermometers instead of observing panting behavior and measuring floor-level wind-chill velocity.
•Allowing nipple drinker lines to sag, causing birds to crouch and spill water directly into the litter.
•Restricting night-time ventilation out of cold-draft fear, causing dangerous CO2 and heat build-up while birds sleep.
•Failing to stir litter early in the day, allowing morning moisture to bake into hard crusts by afternoon.
•At 1.1kg+, rapid growth strains the cardiovascular system; sudden death syndrome (SDS) peaks between Days 21–28. Keep lighting at 5–10 lux during feeding to reduce aggressive pan rushes.
•Clinical escalation trigger: If daily mortality exceeds 0.10% (10 birds per 10,000) or birds display abdominal fluid accumulation (ascites), contact the veterinary technical officer immediately for necropsy and ventilation review.
•Look at the birds, not just the controller: If birds are sitting with wings lifted like fans, your effective air speed is too low regardless of what the thermostat reads.
•Walk the house against the direction of airflow; this prompts birds to stand and release trapped heat from their underbellies into the wind stream.
Heavy broilers are fully feathered and cannot sweat. They lose body heat primarily through convective cooling (air moving across their skin) and respiratory evaporation. An air speed of 1.8 m/s creates a wind-chill effect that reduces effective temperature by 3–4°C without adding humidity.
When birds stand upright to drink, they should reach upward at a 45–60° angle with their beaks pointing up toward the nipple. If birds must lower their heads or bend their necks, water will drip from their wattles into the litter.
First check for leaking nipples or line regulators. If equipment is intact, sudden high water intake accompanied by lower feed intake indicates flock heat stress. Immediately increase tunnel fan capacity and flush drinker lines with cool well water.
Tomorrow, your operation reaches Day 23. The primary management objective will be:
Deliver 322 ml/bird of fresh, cool drinking water at 90–100 ml/min flow rate, sustain 1,225g target weight (+70g gain), and maintain dry, friable litter under high water throughput.
📈Growth & Feed Conversion Calculators
Calculate FCR, Feed Intake & Batch Profit
Benchmark your flock's live feed conversion ratio against standard commercial breed targets and audit final contract growing charge earnings.
