Agriculture and Food 7–12 · Years 11–12

Meat chicken growth and feed conversion trial

Plant/Animal production: Experimental analysis and research in plant/animal systems

Practical, model not builtMedium risk

School laboratory, not for home

In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.

The idea

Weighing meat chickens and their feed each week gives a growth curve and the feed conversion ratio, the kilograms of feed eaten for each kilogram of liveweight gained.

Safety card

Medium riskA teacher supervises

Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

Hazards

Salmonella and Campylobacter from birds and litter
heat lamp fire and burns
stress or injury to birds during handling
dust and ammonia from litter

Controls

hand washing and dedicated footwear for the poultry area
heat lamps secured and clear of litter
calm, brief handling as Animals in Schools describes
keep litter dry and the shed ventilated

Note

NSW Department of Education, Animals in Schools: activity categories and approvals under the Animal Research Act 1985 (NSW). A category 3 activity needs the school's Animal Welfare Liaison Officer to approve it; a category 4 activity needs the Schools Animal Care and Ethics Committee (SACEC) to approve student participation in writing; a category 5 activity needs SACEC certification, renewed every three years, for a teacher demonstration. Two limits on the Animals in Schools fowls page govern this trial directly and are not optional. On diets: "Where comparative food trials are being undertaken, no less than the minimum protein levels should be fed to birds. The maximum amount of protein permitted is 20% above the minimum levels." Both diets in any comparison must therefore sit inside that band, checked from the feed labels against the published minimum for the birds' age, and a diet below the minimum or more than 20% above it is not run. On how long the birds are kept: "Schools should not keep broilers for more than 10 weeks. After this period, the likelihood of stress fractures and broken legs increases." The birds must leave the school before 10 weeks of age, and where they go is arranged in writing before they arrive.

What you need

day-old meat chickens from a hatchery, in numbers the pen space allows
brooder pens with litter, secured heat lamps, thermometers, feeders and drinkers
commercial starter, grower and finisher feeds with labels, with the protein percentage on each label read against the published minimum for the birds' age so a comparison stays inside the Animals in Schools band
triple beam balance for chicks; spring balance and a box or leg loop for older birds (as Animals in Schools describes)
scale for weighing feed, leg bands to mark a sample of birds, record sheets

How to do it

Before the birds arrive, confirm the Animals in Schools categories (weighing is category 2; comparing diets is category 3, and any feeding trial must meet normal nutritional needs and last no longer than needed), obtain approvals, and arrange in writing where the birds go at the end. Animals in Schools sets the end: schools should not keep broilers for more than 10 weeks, because after that the likelihood of stress fractures and broken legs increases, so the trial and the birds' departure are both planned inside that 10 weeks.
Run the brooder at 33 °C for day-old chicks and lower it by 1 °C every 2 to 3 days to 20 °C at 28 days, giving at least 180–200 cm^2 per bird to 2 weeks, 440 cm^2 from 2 to 4 weeks and, after 4 weeks, when the Animals in Schools table lists no band short of adult birds, at least the 0.5 m^2 per bird it gives for adults on deep litter.
Mark a sample of birds in each pen and weigh them at the same time each week, quickly and calmly, returning each bird at once.
Weigh the feed offered and the feed left each week to find feed eaten per pen.
Calculate mean liveweight, weekly gain, average daily gain and cumulative feed conversion ratio for each pen, and plot the growth curve.
If two commercial diets are compared, allocate chicks to pens at random with at least two pens per diet, keep both diets inside the Animals in Schools protein band for a comparative food trial (no less than the minimum protein level for the birds' age, and no more than 20% above that minimum), keep the comparison as short as Animals in Schools advises (ten to fourteen days is sufficient for young birds, after which they return to their normal diet) and test the difference.

What you should see

Weekly liveweight gain increases from week to week over the first weeks, so the growth curve steepens. Feed conversion ratio is calculated per pen; a lower ratio means more efficient growth. As an arithmetic check (not a performance target), 3.200 kg of feed per bird with liveweight rising from 0.042 kg to 2.100 kg over 35 days gives a gain of 2.058 kg, a feed conversion ratio of 1.555 and an average daily gain of 58.8 g. The learner knows it worked when every pen's feed records balance (offered minus left equals eaten) and the weighed sample was the same birds each week.

What changes

What you change: age in weeks (and diet, if two diets are compared)
What you measure: mean liveweight (g), weekly gain (g), feed conversion ratio
What you keep the same: hatch and strain
brooding temperatures
space per bird
water and lighting
time of weighing

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

A lower feed conversion ratio means the birds ate less and so grew less.
Birds can be weighed at any time of day and give comparable results.
A feeding comparison with farm animals needs no approval if the feeds are commercial.
A feeding comparison may use any two diets as long as the birds keep eating.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Agriculture Stage 6 Syllabus (2013)H2.2 H4.1
Agriculture 11–12 Syllabus (2026), new syllabus, implementation from 2028AG-11-03 AG-12-03
Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.

All Concept Studio activities