Feed mill shrink: an old topic that still matters

A long-standing issue

Shrink was one of the first topics I had to deal with when I started working in feed mills more than 30 years ago. Even then, it was already present - sometimes sensitive, often discussed… but rarely structured.

With hindsight, little has changed in substance. Shrink remains a central topic in feed mill management. It concerns production, of course, but also finance, quality, maintenance and, more broadly, the overall performance of the company.

What stands out is the gap between its importance and the level of formalisation it receives. The term is widely known, but definitions vary, methods differ, and practices often remain specific to each site.

In an economic context characterised by low margins - around 0.4% net profit margin (source: Crédit Agricole, France, 2024) - controlling shrink takes on particular importance. Seemingly small deviations can have a significant impact on profitability.

The aim of this article is to provide a global view of the subject, drawing both on field experience and technical literature, in order to better understand the mechanisms involved and identify areas for improvement.

Defining shrink: a necessary starting point

The term “shrink” is widely used in the industry, but it does not always refer to a consistent reality. In many cases, it is associated only with moisture losses, which limits its scope.

A simple definition can be proposed:

Shrink corresponds, over a given period, to the difference between incoming and outgoing material flows, adjusted for stock variations.

This provides a useful framework. For example, if stock levels are identical at the beginning and end of the period, and 100 tonnes enter while 99 tonnes leave, shrink is 1%.

However, this view remains partial. Stocks vary, sometimes significantly, and it is often relevant to include an economic dimension. Losing one tonne of premix does not have the same impact as losing one tonne of grain, and the underlying causes are likely to be different.

An often-underestimated economic issue

In a sector where margins are structurally low, shrink represents a direct economic lever.

Data from international technical literature show that total losses in feed mills can reach 1 to 3% of production, depending on the level of process control. Each operator can easily translate what this represents over a year, both in tonnes and in monetary terms.

In any case, these are significant figures. They help explain why shrink goes beyond a purely technical issue and becomes a matter of management.

A reality that is both visible and less perceptible

Shrink takes different forms. Some are well identified, others much less so.

Visible losses (though not always measured or measurable) include:

moisture losses due to evaporation or drying,
solid losses, for example in the form of dust,
volumes linked to recycling or cleaning operations.

Alongside these, there are less visible discrepancies, often just as important:

data entry errors during intake or dispatch,
stock discrepancies within information systems,
weighing inaccuracies,
routing or material handling errors.

In many cases, measured shrink only reflects part of the reality. This makes analysis more complex and can lead to incomplete interpretations.

Sources of losses throughout the process

Technical work on the subject shows that losses can occur at every stage of the process.

At intake, errors may occur during unloading or material allocation, particularly when systems still rely heavily on manual operations.

Storage is also a sensitive area. Poor visibility of actual volumes or inadequate storage conditions can lead to losses related to moisture or material degradation.

During grinding, the mechanical energy applied to the product can lead to variations in moisture, depending on settings and operating conditions.

Batching operations present a particular challenge in terms of accuracy. Equipment typically allows tolerances in the order of ±0.5%, but deviations still occur, especially for high-value micro-ingredients.

Mixing, pelleting and cooling stages are also sources of variability. For example, inadequate pellet quality, with increased generation of fines, can lead to losses, recycling or rework.

Finally, dispatch operations, whether bulk or bagged, can introduce discrepancies related to weighing systems or logistics management.

The specific role of moisture

Moisture is often highlighted in the analysis of shrink, and rightly so. It is an important component of mass variation.

However, it cannot be considered in isolation. Sources of variation are multiple: moisture of incoming raw materials, storage conditions, effects of grinding, water addition during mixing, steam during pelleting, and evaporation during cooling.

Measurement technologies have improved in recent years, with the development of inline sensors. Even so, it remains difficult to obtain a precise real-time view of moisture flows within the plant. Interpreting measurements often requires a global understanding of the process.

An indicator of overall process control

Beyond its technical components, shrink can be seen as an indicator of overall plant control.

It reflects:

the quality of equipment and settings,
the reliability of measurement systems,
the rigour of operational practices,
and the level of coordination between different functions within the company.

A deviation in shrink is rarely due to a single cause. It most often results from a combination of factors.

Towards a more structured approach

In practice, shrink measurement often remains heterogeneous. One of the first steps is to clarify calculation rules and share them across the organisation.

This involves:

defining a common and consistant method,
improving the reliability of weighing and stock data,
limiting manual data entry where possible,
and segmenting (period/product/lines…) the analysis to better identify sources of deviation.

Integrating a value-based approach, alongside volume, also helps refine the interpretation of results.

Practical levers for improvement

Reducing shrink relies on a combination of actions.

From a technical perspective, automation of flows, improvement and securing of metrology, and optimisation of process settings are key levers.

From an organisational perspective, standardisation of practices, training and team involvement play a central role. A shared understanding of the topic across the organisation is often decisive.

Finally, regular monitoring of indicators and the involvement of different functions within the company help sustain progress over time.

An indicator of industrial maturity

Shrink is an old topic, but it remains fully relevant. It is not limited to a simple material loss. It reflects the level of control of an industrial system as a whole.

Its complexity lies in the fact that it combines physical phenomena, organisational aspects and data reliability issues.

Companies that make progress on this topic are generally those that adopt a structured and shared approach. Not by looking for a single solution, but by working consistently across all available levers.

And this is probably why, despite technological developments, shrink will remain a topic of discussion for many years to come.