Eggs: Grading, Storage & Nutrition
A practical reference for farmers, traders and buyers — how eggs are graded by weight, how to judge freshness, how to hold quality through an Indian summer, and what actually drives the rate you get paid.
1. Egg grading and sizing
Eggs are graded on two things: weight and shell/interior condition. Weight determines the size class you are paid for; condition determines whether the egg is saleable as a table egg at all.
| Grade | Weight per egg | Typical source |
|---|---|---|
| Jumbo | Above 68 g | Older layers, late in the cycle |
| Large | 60–68 g | Peak-production commercial layers |
| Medium | 53–60 g | Mid-cycle commercial layers |
| Small | 45–53 g | Pullets, early lay |
| Pewee | Below 45 g | First eggs of a new flock |
Egg size increases naturally as a hen ages, so a flock moves up through the grades over its laying cycle. Bird weight at point of lay, protein and calcium levels in the feed, and heat stress all shift the average egg weight a flock produces.
Condition grades
- Grade A — clean, unbroken, normal shape; firm white and well-centred yolk. Sold as table eggs.
- Grade B — sound shell but stained, slightly misshapen, or with a thinner white. Usually diverted to processing.
- Rejects — cracked, leaking, or dirty eggs. These must not enter the table-egg chain.
2. Judging egg quality
The float test
Place the egg in a glass of water. A fresh egg sinks and lies flat. As the egg ages moisture escapes through the porous shell and the air cell at the blunt end expands, so an older egg tilts upright. An egg that floats has a large air cell and should be discarded.
Candling
Holding a bright light against the shell in a dark room reveals cracks, blood spots, meat spots and the size of the air cell. It is the standard check before packing and, for hatching eggs, before setting them in the incubator.
What you see when you break it open
- Fresh — the yolk stands high and round; the thick white holds tightly around it.
- Ageing — the yolk flattens and the white spreads thin and watery.
- Cloudy white — a sign of freshness, not spoilage. It is dissolved carbon dioxide that has not yet escaped.
- Blood or meat spots — harmless and safe to eat, but downgraded on appearance.
- Green-grey ring around a boiled yolk — over-boiling, a harmless iron-sulphur reaction.
3. Storage and cold chain
Egg quality only ever declines after lay; good storage slows the decline, it cannot reverse it. In Indian conditions the ambient temperature is the main enemy.
- Store at 4–7°C with 70–80% relative humidity for retail and household stock.
- Point the blunt end up. That keeps the air cell at the top and the yolk centred.
- Do not wash eggs before storage. Washing strips the natural cuticle that seals the pores. Wash immediately before use instead.
- Keep the cold chain unbroken. Repeatedly cooling and warming eggs causes condensation on the shell, and surface moisture helps bacteria get through.
- Keep them away from strong-smelling stock. Shells are porous and eggs pick up odours from onions, fish and spices.
- Move stock first-in, first-out. Date the trays at collection, not at dispatch.
| Condition | Holds acceptable quality for |
|---|---|
| Refrigerated, 4–7°C | 4–5 weeks |
| Cool room, 20–25°C | 7–10 days |
| Indian summer ambient, 35–40°C | 2–3 days |
4. Handling and food safety
- Collect eggs at least twice a day, and more often in hot weather — eggs left in the nest lose quality fastest.
- Keep nest boxes clean and bedded so fewer eggs are soiled at source.
- Handle by the tray, not the individual egg, to limit hairline cracks.
- Wash hands and surfaces after handling raw eggs and shells.
- Cook until both white and yolk are firm where the eggs will be served to children, older people, pregnant women, or anyone immunocompromised.
- Refrigerate cooked egg dishes within two hours, and within one hour in hot weather.
5. Nutrition
A whole egg is one of the most complete and least expensive sources of protein available, supplying all nine essential amino acids.
| Nutrient | Approximate amount |
|---|---|
| Energy | 70–78 kcal |
| Protein | 6–7 g |
| Total fat | 4.5–5 g |
| Carbohydrate | Under 1 g |
| Cholesterol | About 185–200 mg (all in the yolk) |
Most of the vitamins and minerals — vitamin A, vitamin D, vitamin B12, choline, selenium and iron — sit in the yolk, while the white is almost entirely protein and water. Discarding yolks removes the majority of the micronutrients along with the fat.
A hen's diet changes what ends up in the egg. Feeding flaxseed or fish oil raises omega-3 content, and adding marigold extract or maize deepens yolk colour. Enriched eggs are sold at a premium on exactly this basis.
6. What drives egg prices
- Feed cost — maize and soya together make up roughly 65–70% of the cost of producing an egg, so feed markets move egg economics more than anything else.
- Season — demand rises through winter and softens in summer.
- Festival calendar — consumption drops sharply during periods when many households avoid eggs, and recovers immediately after.
- Distance to market — eggs are fragile and bulky, so transport and breakage are a real share of the delivered cost.
- Flock age profile — a region with many flocks in peak lay puts more eggs into the market at once.
Declared rates across most Indian markets are commonly tracked against NECC announcements, which traders use as the reference for daily negotiation.
7. Frequently asked questions
Are brown eggs healthier than white eggs?
No. Shell colour is decided purely by the breed of the hen and has no bearing on nutrition, taste or quality. White Leghorns lay white eggs, Rhode Island Reds and most desi and dual-purpose breeds lay brown or tinted eggs. What actually changes the nutritional profile is the hen's feed and management, not the shell.
How can I tell if an egg is still fresh?
Use the float test. Place the egg in a glass of water: a fresh egg sinks and lies flat on its side, a slightly older egg tilts upward, and an egg that floats should be discarded. As an egg ages, moisture leaves through the shell and the internal air cell grows, which makes it buoyant.
Should eggs be refrigerated in India?
Refrigeration is strongly advisable in most of India. Unwashed eggs keep their natural protective cuticle and can hold for a few days at cool room temperature, but at 30-40°C ambient temperatures quality falls quickly. Store at 4-7°C for retail and household use, and keep the cold chain unbroken — repeated warming and cooling causes condensation, which helps bacteria penetrate the shell.
What is the difference between table eggs and hatching eggs?
Table eggs are unfertilised and produced for consumption. Hatching eggs are fertilised, come from a breeder flock, and are handled under far stricter conditions of temperature, humidity and turning because they must remain viable for incubation. The two are graded and priced separately.
How many eggs does a commercial layer produce in a year?
A well-managed commercial layer typically produces 280-320 eggs across a laying cycle of roughly 72-80 weeks. Improved backyard birds such as Vanaraja or Gramapriya lay around 130-180 eggs a year, and indigenous desi hens usually lay 60-100.
Why do egg prices change so much through the year?
Demand is seasonal. Consumption rises in the cooler months and falls during summer and during festival periods when many households avoid eggs. Feed cost — mainly maize and soya — is the other major driver, since feed is roughly 65-70% of the cost of producing an egg. Declared rates in India are commonly tracked against NECC price announcements.
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