science

Legbar

Legbar is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Legbar rather than just read about it. In short: The Legbar is a rare British auto-sexing breed of chicken. It was created in the early twentieth century by Reginald Crundall Punnett and Michael Pease at the Genetical Institute of Cambridge University.

Key takeaways

Legbar belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Legbar to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Legbar from memory before moving on to harder problems.

Reference excerpt

The Legbar is a rare British auto-sexing breed of chicken. It was created in the early twentieth century by Reginald Crundall Punnett and Michael Pease at the Genetical Institute of Cambridge University. They cross-bred American barred Plymouth Rock birds with brown Leghorns and created the gold and silver colour varieties. Pease created a cream Legbar by cross-breeding these with white Leghorns; later crossing with Araucanas caused this to have a crest and to lay blue or blue-green eggs.

History The Legbar was the second auto-sexing chicken breed created by Reginald Crundall Punnett and Michael Pease at the Genetical Institute of Cambridge University, after the Cambar, which was created in 1929 by crossing barred Plymouth Rock with gold Campine birds. The Legbar arose from cross-breeding of Plymouth Rock birds with brown Leghorns, which at that time were two of the principal egg-laying breeds. As with the Cambar, they set out to breed a bird that would both have brown down and carry the barred gene (B), so that chicks would have sex-linked plumage differences that could easily be distinguished. Standards for the gold and silver colour varieties were drawn up in 1945 and 1951 respectively. The cream Legbar was created by chance. Through cross-breeding of gold Legbars with white Leghorn stock, Pease had obtained some cream-coloured birds; their eggs were white, and they had no crest. An experimental crossing of these with some cream-coloured Araucanas from Punnett's laboratory led to the creation of the cream Legbar, a crested layer of coloured eggs for which a standard was drawn up in 1958. Within a short time it became very rare, but has since recovered. It is treated by the Poultry Club of Great Britain as a colour variety of the Legbar, but is considered by the Rare Breed Survival Trust to be a separate breed. Both the Legbar and the Cream Legbar are listed among the UK breeds on the watchlist of the trust; neither is considered "priority".

Characteristics The Legbar has three colour varieties: gold, silver and cream. The cream variant has a crest and lays blue, olive or green eggs. The Legbar is considered a rare breed by the Poultry Club of Great Britain; until the Autosexing Breeds Association was re-formed in 2016, it fell under the Rare Poultry Society.

Use The Legbar was bred as an auto-sexing layer breed. Hens may give 180 eggs or more per year.

References

Illustrations

Worked examples

Example 1 — a first encounter with Legbar

Start with the simplest possible case. Write down what Legbar claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Legbar before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Legbar ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Legbar

In research: Legbar appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Legbar in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Legbar is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal breeds on the RBST Watchlist, Auto-sexing chicken breeds, Chicken breeds, so understanding it makes those chapters shorter.
In everyday life: Look for Legbar outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Legbar in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Legbar means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Legbar out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Legbar in simple terms?

Why does Legbar matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Legbar?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Legbar.