Onset of production (18-25 weeks)

Period after transfer

During the first days after housing, it is important to stimulate sufficient feed intake. The hens should increase their feed intake as fast as possible and continue gaining weight (see figure 1).
Some useful recommendations:

  • Provide attractive feed with a good structure that avoids fine particles.
  • Provide good quality, fresh water.
  • Run the feeding lines frequently during the day.
  • Feed on an empty feeder.
  • Ensure there is enough light at the feeder.
  • Light intensity should be higher in the laying house than in the rearing house.
  • Avoid excessive stimulation when transferring birds to open houses.

Light and light programs

There are two main factors that stimulate the onset of laying in the flock:
Some useful recommendations:

  • Body weight
  • Photoperiod

In the absence of other stimuli, hens will begin to lay when they reach an appropiate body weight . However, the duration of the photoperiod can stimulate or delay the onset of lay as follow:

  • Stable or increasing photoperiods with a duration exceeding 14 hours will early stimulate the onset of lay.
  • Stable photoperiods with a duration of less than 14 hours will delay the onset of lay.

Decreasing photoperiods should never be used in production period.

How to choose the right stimulation age

Normally a flock should be kept with a stable photoperiod until light stimulation starts. If hens are in the weight range, a standard recommendation for standard production is 119 days of life. However, this may vary according to two factors:

  • Flock body weight status: If the birds’ body weight is far below the standard it is preferable to delay light stimulation for at least one week. Equally, if the CV is very high and the weight of part of the flock is far behind the standard, later light stimulation is preferable.
  • Accumulated egg weight objective: egg size strongly correlates with the size of the bird. A simple way to get heavier birds in the production on- set is to delay light stimulation. Age at 50 % lay and body weight at 50 % lay are two values that can greatly help to forecast the egg weight.

How to deal with natural day length

The light program in open houses should take the natural day length at the stimulation age into account. Determine the light program during rearing as explained in chapter growing. Stimulation should differ depending on the day length.

  • Increasing day length period: flocks risk being stimulated by natural light before they reach the correct body weight. To avoid this, the artificial day length should always be longer than the natural day length until the flock is ready to be stimulated. This should be considered in the rearing light program.
  • Decreasing day length period: flocks exposed to decreasing day length can show delayed onset of lay. To avoid this, create an artificial day length longer than the natural day length from week 10.

To achieve this goal, use the app: H&N lighting program.

How to apply light stimulation in a flock

Once the light stimulation age is defined, light stimulation starts with an initial photoperiod increase. Take the following into account:

  • Increase the day length at least one hour after sunset, or after switching off the lights.
  • Light intensity control in the laying house should be slightly higher than in the rearing house.
  • Light distribution should avoid dark area and shady areas
  • Keep light sources clear.

Subsequently, the photoperiod must be increased weekly. Light increases should be at least half an hour, although a higher increase is possible if the laying percentage increases rapidly. The more light hours the hens have, the more time they will use to consume feed. It is therefore important to achieve at least 14 hours of light to allow the flock to reach a proper feed intake.

Sexual maturation and onset of lay

At the start of their productive life, hens develop their secondary sexual characteristics. This is a good indication that the bird’s hormone development is correct. In addition to the start of the reproductive capacity (and therefore production of eggs) other changes occur in the bird’s metabolism.

One of the most important is the ability to capture calcium to create intramedullary bone. It is very important that the birds develop this type of bone to ensure good quality eggshells during the late lay period. Good practice is to use a pre-lay feed as explained in chapter nutrition.

Management to peak production period


The birds need a good quality feed, with the structure and nutrient density necessary to suit their feed intake as well as provide their egg production, growing and maintenance requirements. Nutrient requirements in this phase increase rapidly so the feed intake of the birds should increase simultaneously. If not then the birds’ nutrient requirement will not be met and they will be forced to mobilize their reserves. This may lead to soft bones and potentially harm the bird for the rest of the laying cycle. Switching to a layer diet with more than 2.5 % calcium stimulates the birds to lay eggs. This feed phase I aims to cover the requirements to obtain the maximum egg mass. See nutrition chapter for further details of feed recommendations.

Ventilation & temperature

Proper ventilation should be used to guarantee good air quality in the house, and ensure a low concentration of gases and dust. At the same time the temperature in the house should be optimally maintained between 18–24 °C with a relative humidity of 50–60 %. Birds do not tolerate temperatures above 30 °C well, especially if high temperatures are combined with high humidity. During heat stress, ensure that sufficient air circu- lates around the birds. The use of additional fans as well as evaporative coolers should be considered to reduce the house temperature.


Cool water of good quality should always be available with the required water flow. Continuously monitor the water quality. Water consumption is normally 1.5–2 times higher than feed consumption. It is highly recommended to monitor the water consumption for early detection of possible problems. Regular cleaning and flushing of the water lines as well as the supply water tank is essential. Water consumption will clearly increase at 10–14 days prior to the onset of lay. During this period, the ovary and reproductive organs and medullary bone will develop, and water will be stored in the follicles of the ovary.


The birds should have enough space, especially in hot climates. Important aspects are not only cm² of cage floor/bird, but also the height of the cage and how many cm of feeder, and how many drinkers are available per bird. The temperature should be between 18–24 °C.


Onset of lay


Monitoring production data is essential for timely intervention in response to any issues that occur in the weeks between the first eggs and the production peak. Production data should be monitored daily or at least weekly.This should increase daily. During the first week, the increase may be small, but a bigger increase should be seen every day afterwards. In the middle part of onset of lay, the increase should be stronger: at least 2 % per day and ideally close to 3 %. Finally, in the last weeks, the increase should be close to 1 % until the production peak is reached. The rate of increase cannot be monitored correctly if the eggs are collected at different times.


Increases could be a little erratic as not all the hens develop their repro- ductive system at the same time. However, body weight should never decrease, and a clear growth trend should be observed.


As mentioned, consumption should increase every day. Water is the easiest parameter to monitor daily and is a critical management measure.