A 2020 meta-analysis of twelve controlled studies, published in the peer-reviewed poultry literature, found that heat-stressed broilers ate less, gained less weight, and converted feed roughly 0.17 points worse than birds kept in thermal comfort. Mortality told the starkest story: the odds of death under heat stress were about 3.7 times higher than in a controlled house. In plain terms, a flock that should lose 3% can just as easily lose 10% or more once the shed overheats night after night.

Feed is the biggest single cost on a broiler farm, so a shift from an FCR of 1.65 to around 1.90 does real damage.

Mortality compounds it: every bird that dies before harvest is a chick you paid for and feed you already bought, with no sale at the end.

To make the numbers concrete, here is an illustrative 10,000-bird floor house on a 42-day cycle, priced off current Mozambican market rates. Day-old chicks from integrated producers such as Higest were listed at about MZN 55 each in 2025. Broiler feed runs roughly MZN 48 to 54 per kg.

Live broilers were being bought by processors at around MZN 110 to 131 per kg, depending on weight.

The difference between the two sheds is about MZN 430,000 per cycle on the same number of birds, driven almost entirely by feed efficiency and mortality, not by feed price. Run six cycles a year and the gap passes MZN 2.5 million.

The example above is illustrative, but the mechanism is exactly what the published data predicts: cooling the air and keeping it moving lets birds eat, drink and convert feed normally even when it is 33 C outside. A negative-pressure tunnel-ventilation system with evaporative cooling pads, paired with automatic pan feeders and nipple drinkers, holds the house in the birds' comfort zone through the hottest part of the day.

This matters more in Mozambique than in temperate markets because the heat penalty applies to most cycles, not just a few weeks. The government's PROCAVA programme, backed by a US$33 million African Development Bank facility, is explicitly funding hatcheries, feed mills and processing infrastructure, but the house environment is still the grower's own responsibility and the weakest link in the chain.

·Size ventilation for the worst month, not the average. Mozambique's October to November shoulder season is when heat spikes hit the youngest flocks.

·Pair cooling with automatic feeding and drinking so birds can eat during cooler night hours without extra labour.

·Treat biosecurity, foot dips and vaccination against Newcastle and Gumboro as non-negotiable.

A disease event wipes out far more than a hot week ever will.

·Model your own numbers before borrowing. Local agri-loan rates are high, so a house that loses money in hot months cannot service its debt.