Feed Capacity Development in Pullets: A Focus on the Developer Ration

In the early phases (starter and grower), nutrient density is high to support the rapid growth of the organs, the skeletal structure, and the lean tissue. This is achieved by providing the starter and grower feeds in a crumble form to achieve high nutrient intake with a smaller volume of feed. As the bird matures, nutrient requirements shift, and the focus moves toward building adequate body reserves without compromising future productivity. Although these stages differ in nutrient specifications, they have a common dependence on feed intakes. Breeder guides also demonstrate that average daily feed intake rises steadily through late rear from 65 g/b/d at 10 weeks to approximately 80–84 g/b/d by 18 weeks of age, then steps up again in early lay from 118–130 g/b/d.

Importance of Feed Intake Capacity:
A pullet’s genetic potential is realised only when daily nutrient requirements are met. As diets become less nutrient-dense, the pullet must compensate by increasing voluntary feed intake. Birds failing to do so experience:
     • Sub-optimal body weights
     • Reduced uniformity
     • Poor skeletal mineralisation
     • Weaker onset and persistence in lay

The developer period is therefore a controlled “training phase” during which pullets are physiologically and behaviourally conditioned to consume higher volumes.
During the starter phase, there is a high requirement for protein growth. The starter and grower are nutrient-dense rations designed to support the rapid growth phase of the pullet, and nutrient intakes can be further improved by crumbling or pelleting the feed. While it is beneficial to feed pelleted/crumbled feed, it is advisable to feed the developer as a coarse mash to further encourage the stretching of the crop and to have the gizzard work more to grow in size, and slow down the rate of passage to have the intestines increase in volume and increase in their nutrient uptake capacity.
 
The role of the developer ration:
The developer ration plays a strategic role in this phase. It is intentionally formulated with a moderate nutrient density and higher structural fibre to gradually increase feed intake to enable the birds to cope with the mineral-heavy layer diets. The goal is not to increase growth rate but to encourage the bird to increase voluntary feed consumption and develop the physical capacity of the gastrointestinal tract.

The results are:
     • Expand GIT capacity
     • Stimulate gizzard activity through dietary fibre
     • Encourage higher voluntary feed intake
     • Prepare the skeleton for future calcium loads

The table below shows that between 11 and 17 weeks, the pullet must be able to increase feed intake from 70g per day to 95g of feed that is coarser and bulkier. This is in preparation for the expected 115 – 120g per day feed intakes during the transition to the production rations.

Table 1: Expected feed intake changes and feed form for a growth pullet.

Management that unlocks intake capacity:

Feeding schedule and “empty-feeder” technique:
From 10–12 weeks, introduce gap feeding or short empty-feeder periods. This trains crop stretch and ensures birds eat the full ration, not only preferred particles.

Feeder and drinker access:
Limited space restricts smaller birds and negatively affects flock uniformity. Ensure adequate access for all birds.

Water – the hidden intake limiter:
Typical feed-to-water ratios should be 1:1.2–1.4 in rear, increasing as birds age. Check water pressure and drinker height regularly, and keep lines clean. Any water restriction will immediately reduce feed intake.

Temperature and environment:
High temperatures reduce feed intake, while cold conditions increase energy demand at the expense of feed volume and proper training. Keep house temperatures within breed guideline ranges.

Feed texture control:
Regularly check particle size distribution using a sieve shaker. Aim for most particles between 1–3 mm, with fines below 15%. Too many fines lead to a smaller gizzard, faster feed passage, and reduced nutrient absorption. Feed that is too coarse can cause selective feeding.
 
Consequences of poor feed capacity development:
Failure to stretch feed intake during the grower–developer transition can have long-lasting effects:
     • Reduced body weight and poor uniformity at the point of lay
     • Lower peak production potential and low egg mass
     • Slower adaptation to layer diets, delaying the onset of lay and reducing early egg mass

These challenges are difficult to correct once the bird enters lay, making the developer phase a critical window of opportunity for sustained egg production.

Conclusion:
The developer phase is a critical period in pullet rearing. It is not just a step between grower and pre-lay diets, but a deliberate strategy aimed at establishing the bird’s long-term ability to physically consume sufficient feed. By gradually decreasing nutrient density and increasing dietary fibre, producers can encourage higher feed intake capacity, better prepare pullets for the bulkier layer diets, and set the foundation for optimal performance in the laying house. Proper attention to this stage ensures healthier birds, stronger production curves, and improved lifetime egg output.

Should you require more information relating to the feed capacity development in pullets, please contact your nearest De Heus Technical Specialist - https://www.deheus.co.za/meet-our-team/.