When to Harvest a Broiler: Reading the Bird, Not the Calendar

TL;DR: The buyer’s target weight usually decides the date, not the calendar. Weigh a sample from different parts of the house rather than judging by eye. Holding birds past target is the classic mistake: feed conversion worsens with age, so each extra kilo costs more than the last, while leg, heart and heat-stress risk all climb with weight. Withhold feed before slaughter, keep water available. In a hot spell late in the cycle, harvesting beats holding.

The whole broiler enterprise is decided in the last week, and mostly by whether you can resist waiting a few more days.

The Buyer Usually Decides

Market buyers, traders and contract arrangements generally want a specific weight range, and a bird outside it is discounted or refused.

So the practical sequence is:

Find out the target weight your buyer wants — before the cycle starts, not at the end.
Weigh a sample as you approach it.
Harvest when the average hits the range, not when the calendar says a number.

If you are growing for your own household, you have more freedom — but the economics below still apply.

Weigh a Sample, Do Not Eyeball It

Judging weight by eye is unreliable, and in a house full of birds it is unreliable in a way that costs money.

How to sample:

Take birds from different parts of the house — near the feeders, in the corners, at both ends. Birds near feed are heavier, and sampling only those flatters your average.
Weigh enough birds to see the spread, not just the average.
Record it, so you can see the growth rate between weighings and predict the date rather than discovering it.

Wide spread means a management problem, not just a weighing problem — usually feeder or drinker competition, heat, or disease. See coop space per bird, DIY chicken feeder and broiler mortality causes.

Why Holding Them Longer Loses Money

Two forces work against you, and both accelerate.

1. Feed conversion worsens with age. A young bird converts feed to weight efficiently; an older, heavier one does not. Every extra day past the target buys a smaller weight gain for the same feed. Our feed conversion ratio guide explains why that single number decides broiler profitability.

2. Risk climbs with weight. Fast-growing broilers carry structural problems that get worse the longer and heavier they go:

Leg weakness and lameness.
Heart and circulatory problems.
Heat intolerance — a heavily muscled bird generates a lot of metabolic heat and sheds it poorly. See heat stress in chickens.

Our Cornish Cross guide covers why these are built into the growth curve rather than being bad luck. Deciding the harvest date before the chicks arrive is the standard advice for exactly this reason.

The heat exception is worth stating plainly: if a hot spell hits late in the cycle, harvesting sooner is often the right call. Dead birds have no dressing percentage.

Before Slaughter

Withhold feed for a period beforehand, with water still available. An empty crop and gut make evisceration cleaner and reduce contamination risk — see how to dress a chicken.
Handle birds gently. Bruising from rough catching shows in the carcass and costs you quality as well as yield.
Catch in the cool hours, not the middle of a hot afternoon.
Have the processing or the buyer arranged before you catch, not after.

Harvesting in Stages

If the flock is uneven, some growers take the heaviest birds first and leave the rest a few more days.

Advantages: the biggest birds go before their risk climbs further, and removing them relieves crowding and feeder competition, which lets the smaller birds catch up.

Costs: more handling events, more disturbance, and a longer overall cycle for the tail of the flock.

Worth doing when the spread is wide. Not worth doing routinely — a flock that always needs staged harvest is telling you the feeders, the space or the heat management needs fixing.

The Number That Actually Matters

Not the harvest weight. Cost per kilo of saleable meat.

That takes three things you can measure:

Feed conversion ratio — feed in per kilo of live weight.
Dressing percentage — share of live weight you can sell.
Total cost including chicks, feed, health, losses, housing and your time.

Do that once and the harvest decision stops being a guess. See dressed chicken prices and is poultry farming profitable for the selling side.

The Honest Limits Here

That feed conversion deteriorates as broilers age, and that leg, cardiovascular and heat-tolerance problems increase with weight in fast-growing strains, is documented in poultry science and industry practice. This guide gives no target weights and no ages in days, because those belong to the strain you are raising and to the buyer you are selling to — ask your chick supplier for the strain’s management guide, which will include a growth curve, and ask your buyer what weight range they want. Weigh your own sample rather than working from either.

Frequently Asked Questions

When should a broiler be harvested?

At the weight your buyer wants, which is usually the deciding factor, and before feed conversion deteriorates enough that extra days stop paying for themselves. Commercial cycles are short by design.

What happens if I keep a broiler longer?

Feed conversion worsens as the bird ages, so each extra kilo costs more feed than the last. Leg and heart problems also become more likely, and mortality risk rises with weight and heat.

How do I know the birds are ready?

Weigh a sample rather than judging by eye. Pick birds from different parts of the house, weigh them, and work from the average against your buyer target.

Does the buyer decide the harvest date?

Usually. Market and contract buyers want a specific weight range, and a bird outside it is discounted or refused, so the target weight sets the date more often than the calendar does.

Should I withhold feed before harvest?

Feed is withheld for a period before slaughter so the crop and gut are empty, which makes evisceration cleaner and reduces contamination risk. Water stays available.

What if the birds are uneven in size?

Uneven flocks usually mean feeder or drinker competition, heat, or disease. Some growers harvest in stages, taking the heaviest first, which also relieves crowding.

Does heat change the harvest decision?

Yes. Heavy birds are the most vulnerable to heat stress, so a hot spell late in the cycle is a real argument for harvesting rather than holding.