Thinning of broilers — how to reduce the stress
Thinning is catching part of the flock before the end of the cycle, to lower the stocking density and take out the lighter birds. It gives the rest more room and fits the weight market, but it is a major stress for the flock and a real biosecurity risk. We explain how to plan it so as to limit injuries, the disruption of drinking and feeding, and the threat of bringing in disease.
verifiedFrom the team that has organised work on poultry farms for years.
Thinning, also called a partial catch, is taking part of the birds out of the house a few to a dozen or so days before the end of the cycle. Usually the lighter birds are taken, going to the smaller-carcass market, while the flock that stays gets more room at the feeder and the drinker. The stocking density drops and the remaining birds have better conditions for further growth. The procedure itself is short, but like any catch it means noise, movement and contact with people and equipment from outside.
Why is thinning done and how does it differ from a full pickup?
There are three reasons: density, the welfare of the remaining birds and matching the weight market. Cutting the density after thinning improves house conditions in the last phase of rearing, and different bird weights let you serve different buyers. A full pickup ends the cycle and empties the building, while thinning is partial — the flock lives on, and every risk the catching crew brings applies to the birds that stay. The exact course of a full load we describe separately under broiler live-bird pickup; here we focus on what is specific to a partial catch and on limiting its effects.
What happens to the flock during thinning
Every partial catch is a balance: the benefit of lower density against the stress and threats that have to be limited on purpose.
Stress and injuries during catching
Catching, carrying and crating is strong stress for the birds, and haste risks injuries — bruises, scratches, fractures. It hurts not only the birds being taken but also those that stay, running in panic and trampling one another. A calm, trained crew and a steady pace limit losses on both sides.
Disruption of drinking and feeding
During the catch the drinking lines and feeders have to be lifted, and the birds are flushed off the whole floor. For a few hours the remaining flock loses normal access to water and feed and its calm rhythm of drinking and eating. The shorter the disturbance and the faster the lines come back down, the smaller the mark thinning leaves on the remaining birds.
Biosecurity risk of crew and equipment
This is the biggest threat of thinning: people, containers and vehicles from other farms enter a live, unfinished flock. Dirty hands, footwear or crates can carry or “drift” disease into birds that will stay for many more days. That is why crew hygiene, clean equipment and entry control matter more in a partial catch than in a full pickup.
Feed withdrawal before pickup
Before the catch, feeding is withheld to limit contamination and protect the welfare of the transported birds, while access to water is kept per the rules. The problem is that the withdrawal covers the whole flock on a given floor, including the birds that stay. Good timing of the withdrawal and a quick return of feed after the catch limit its effect on the rest of the flock.
Partitions and catching only part of the floor
To avoid flushing the whole house, part of the building is fenced off with partitions and birds are caught only from the marked zone. The rest of the flock stays calm, keeps drinking and eating, and the stress and withdrawal touch a smaller group. Partitioning is one of the most effective ways to a gentler thinning.
Dimmed and blue light
Birds are calmer under heavily dimmed light, so the catch is usually run with the main lights off. Blue light helps, as birds are then less skittish and easier to gather carefully. A calm, dark setting reduces panic, trampling and injuries.
Gentle thinning step by step
- 1
Plan the date, bird count and hours
Agree with the buyer how many birds and at what weight come out in the thinning, and at what hour the transport will arrive. It is best to catch in the cooler, dark part of the day. A good hourly plan shortens the time the flock is flushed and the drinking and feed lines are lifted.
- 2
Set the withdrawal and keep water access
Set the time of withholding feed before the catch per the guidance, taking care that the withdrawal is no longer than needed. Leave the birds access to water as long as possible. Remember the withdrawal will also cover the birds that stay — the shorter and better-planned it is, the better for the rest of the flock.
- 3
Fence off the catching zone with partitions
Divide the floor with partitions and take birds only from the marked part of the house. Leave the rest of the flock calm, with access to water and feed. Catching in batches from smaller zones reduces panic, trampling and the number of birds exposed to stress at once.
- 4
Dim the light and mind the pace of work
Dim the house heavily, and if you can, use blue light — the birds will be calmer. Agree with the crew on a calm, even pace of catching and crating, without the haste that ends in injuries. It is better to work steadily than to jolt the flock in bursts.
- 5
Enforce biosecurity of crew and equipment
Let onto the farm only clean people, in clean clothing and footwear, with washed and disinfected containers and vehicles. Control the entry, route vehicles along the marked path and do not mix the dirty and clean zones. This flock lives on, so any lapse of hygiene can cost it its health in the following days.
- 6
Restore conditions and watch the remaining flock
After the catch, lower the drinking lines and feeders as soon as possible, restore the light to normal and resume feeding. For the next days watch water and feed intake, bird movement and any symptoms — thinning is a moment after which it is easy to miss the start of a problem in the flock that stayed.
Frequently asked questions about broiler thinning
How does thinning differ from an ordinary live-bird pickup?add
Thinning is a partial catch — only part of the birds, usually the lighter ones, is taken, and the rest of the flock stays in the house for more days. A full pickup ends the cycle and empties the building. The difference is crucial, because in thinning every risk of the catch — stress, withdrawal, contact with an outside crew — applies to birds that live on, so their health depends on how carefully and hygienically you run the procedure.
Why is thinning so big from a biosecurity point of view?add
Because people, containers and vehicles that the same day may be on other farms enter a live, unfinished flock. Dirty footwear, hands or crates can carry or “drift” disease into birds that will stay for many more days. With a full pickup the building goes to cleaning and disinfection anyway, while with thinning a possible infection has time to develop in the remaining flock.
How to reduce stress and injuries during catching?add
Catch under heavily dimmed, ideally blue light, fence off the zone with partitions and gather birds only from part of the floor, so as not to flush the whole house. Rely on a calm, trained crew and an even, unhurried pace, because it is haste that ends in bruises and trampling. The smaller the group at once and the calmer the setting, the fewer losses on both sides.
What about feed withdrawal and drinking in thinning?add
Feeding is withheld before the catch per the guidance, to limit contamination and protect the welfare of the transported birds, but access to water is kept as long as possible. Remember the withdrawal will also cover the birds that stay — so plan it as short as possible and, as soon as the catch ends, lower the drinking lines, restore feed and bring the house back to its normal rhythm.
Run pickups and thinnings in DlaFerm.pl
In DlaFerm.pl you record the thinning and the full pickup in the digital flock card, note every entry and exit in the entry/exit log, and handle the catching crew in the crew programme — all in one place. Create a free account or write to us.
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