Regulation is coming: What are the different ways to measure keel bone damage?

Regulators are increasingly focussed on collecting animal-based welfare indicators, and keel bone damage is often on the agenda. The European Food Safety Authority's 2023 opinion named keel bone fractures as a priority parameter to monitor, and the EU Platform on Animal Welfare process has identified keel bone damage as one of five provisional welfare indicators for laying hens, expected to feed into forthcoming regulation. Similar requirements may well follow in the UK, the US, and the wider developed world. Regardless of the regulatory timetable, effective monitoring of keel bone health is essential to maintaining strong flocks.^[1]

Wherever you sit in the egg supply chain, the direction of travel is the same. Measurement is coming, and those who understand the options now will be able to prepare for it, and to influence the standards before they are set rather than inherit ones that don't work in practice. For producers in particular, the same data does a second job: routine measurement is the only reliable way to know whether the money you spend on housing and management is improving the bone health of your flocks, and therefore avoiding the productivity impacts associated with keel bone damage. Getting ahead of this is both a regulatory preparation and a management tool.

Different measuring techniques: the cost–accuracy trade-off

There is no single "best" way to measure keel bone damage. Every method sits somewhere on a curve between cost and accuracy.

Research-grade methods: CT and dissection

Computed tomography (CT) and physical dissection of the keel after slaughter are the most accurate methods of all. Dissection is the true gold standard against which every other method is validated, and CT provides a complete three-dimensional picture and can even track damage over time in living birds.^[3] Both are essential research tools. Neither is remotely practical at commercial scale: they are expensive and slow. These are tools for researchers, not for routine industry use.

Radiography: accurate, but expensive

X-ray imaging is accurate. It detects fractures without callus, sees the hidden upper surface of the keel, and can distinguish multiple fractures, and standardised scoring systems now achieve excellent agreement between assessors.^[5] This makes it the workhorse of research and of genetic-selection programmes, where breeders increasingly use rapid live-bird X-ray to identify birds with stronger skeletons.

But the equipment runs to tens of thousands of pounds, requires radiation-safety training, and is slow on a per-bird basis. It is not realistic as a routine, every-flock monitoring tool. Its place is as a high-accuracy reference method (including, potentially, periodic spot-checks to calibrate cheaper methods) rather than the everyday measure.

Palpation: the check producers can run today

Palpation, running a trained hand along the keel to feel for healed fractures and irregularities, is the only method in routine use today, because it needs no equipment. It is the basis of most current on-farm assessments, and it is the one technique a producer can use to check their own flock, on their own farm, right now.

Its weaknesses are well documented. Palpation relies on feeling callus, the thickened tissue that forms as a fracture heals, but a large share of fractures never develop detectable callus, and recent fractures have none yet. Crucially, more than 60% of fractures occur near the caudal tip of the keel, which is the hardest part to assess by touch, and fractures on the upper surface are hidden by breast muscle entirely.^[4] The result is a method that systematically under-counts damage, and that gives different answers depending on who is doing the assessment.

So palpation is best understood as a useful, low-cost screen for keeping an eye on your own birds, not as a defensible audit standard on its own. Used regularly, with proper training, it still tells a producer a great deal about how their flock is faring.

Camera-based systems: the most promising route

This is where the cost–accuracy curve becomes interesting. Automated camera systems assess birds visually and, once installed, the cost of measuring each additional bird is essentially nil, which is exactly the property routine, full-flock monitoring needs.^[6]

A camera also brings advantages no human assessor can match. It does not get tired, does not need to handle birds, and gives the same answer every time. That repeatability is precisely what an auditable standard requires, and it removes the assessor-variability problem that dogs palpation. Additionally, the infrastructure is already partly there: processors increasingly photograph birds for carcass grading and foot-health assessment, or meat quality, so adding a keel module to an existing imaging line is a comparatively low-cost extension rather than a new capital programme.

Camera-based monitoring is still maturing, and the accuracy of automated detection needs further validation against X-ray and dissection. For that reason we hold this recommendation lightly rather than firmly, but on the combination of low marginal cost, full-flock coverage and auditability, it is the most credible route to routine, affordable measurement, and the direction regulators, certifiers and the wider industry should be building towards.

Why the slaughter line is the right place

The slaughter line is the most efficient occasion to measure a flock.

First, every bird passes through it. Instead of assessing a sample of 50 birds per flock, a slaughter-line system can in principle assess the whole flock.

Second, the birds are already gathered and presented uniformly. On the farm, any measurement means catching and handling birds, which is labour-intensive and stressful for the flock. At the slaughter line that work is already done: the birds arrive in a consistent, accessible flow.

Third, it is a consistent point in the bird's life. Every flock reaches slaughter at a broadly comparable age, so measurements are taken at the same life stage. On-farm assessments have to be harmonised for flock age before they can be compared, which slaughter-line data largely sidesteps.

The one trade-off is timing: slaughter-line measurement is retrospective. You learn about a flock's keel health after it has gone, so it cannot give you live, in-cycle feedback for that flock. Its value is as a reliable record that informs the next flock, benchmarks farms and systems against each other, and gives regulators and certifiers a defensible figure. This is why the EU sub-group has landed where it has:

What this means for you

For regulators and certifiers: the long-term goal should be automated, camera-based assessment at the slaughter line, objective, full-flock, and auditable in a way palpation can never be. Standards and infrastructure should be pointed in that direction now, so that the measurement capability is ready as requirements firm up.

For producers: you have limited direct control over what happens at the slaughter line, but you have every reason to support the move towards it. The resulting data is about your flock and your management, and you are the one who benefits from it. In the meantime, don't wait. Palpation lets you keep an eye on your own flock's keel health today, and acting on what you find is good for both your birds and your bottom line. We strongly encourage producers to palpate their flocks regularly. Get in touch if you would like support or advice.

Stronger Flocks is working to develop and validate the automated, slaughter-line systems this will ultimately need. If you would like to share your views, or get involved with implementation at your facility, please reach out to hello@strongerflocks.com.