Factors Affecting Egg Quality

Many factors affect egg quality. Sometimes the cause is not a single factor but a combination of factors. A few of these problems can be prevented or reduced by good hen management. Producers should remember that genetics, feed quality and environment play a role in egg quality. The most reliable factor is age. A young pullet produces smaller eggs with strong egg shells and albumen that stands high. As the hen ages, the shells thin, and the albumen begins to weaken and run. Hens can be molted to induce another egg cycle, which will improve egg quality, or they will need to be replaced with young pullets.

The following charts summarize factors that may affect egg quality and suggest corrective measures. As more emphasis is placed on egg quality, it is important that all possible defects be eliminated. When defects are found, consult the chart for possible causes and solutions.

The Shell

Condition	Causes	Corrective Measures
Thin, sandy, misshapen, rough, ridged or soft	Age of hens	Replace after 12 to 14 months of lay
	Arasan, Tetrame Thylthiuram Disulfide); used to control mold and fungus growth	Do not include arasan treated grains in the diet of layers. Law requires that treated grain be dyed.
	Sulfanilamide (sulfa drugs)	Use according to accepted recommendations
	High constant temperatures	Control temperature. Provide plenty of water
	Respiratory diseases (Newcastle, infectious bronchitis and laryngotracheitis)	Follow a recommended program for vaccination and disease prevention in poultry
	High salt (NaCl)	Feed less salt
	Drugs for rodent control	Keep rat bait away from poultry
	Fright	Avoid sudden noises. Approach birds cautiously
	Reduced calcium intake	Provide 3 percent calcium during cool weather Provide 4 percent calcium during warm weather
	Heredity	Select strains that produce eggs of good shell
Abnormal color (brown to yellow)	Nicarbazine; a treatment for coccidiosis in broilers	Do not feed to layers
	Chlortetracycline (600-800 gm/ton), Aureomycin	Use according to accepted recommendations
	Gas lead in lines or burners	Maintain tight connections in gas line, keep burners in excellent working condition and provide ventilation in areas where gas is used to heat egg rooms
White to brown	Iron (FeSO₄), (7H₂O) 0.1 ppm	Have iron content checked in water used for washing eggs. Keep below 0.1 ppm
Faded color	Low calcium in diets of turkeys	Raise calcium levels for increased shell color and improved shell thickness
Mottling of shell (bright spots or moist appearance around pores, observed by candling)	Water retained by protein in spongy layer of the shell	Do not mistake for a crack or cracks in the shell. Maintain 80 percent humidity in egg room
Porosity	Age and breed of hens, environmental temperatures, and season of year	Keep hen house cooler, hold eggs in cool place, sell hens after 12 to 14 months of lay or molt, and select strain bred for good shell texture
Tremulous or moving air cell (observed by candling)	Rough handling	Observe and make necessary alterations in egg-handling practices
Tainted shells	Paradichlorbenzene (moth repellant)	Do not feed to birds

The White (albumen)

Condition	Causes	Corrective Measures
Pink egg whites	Cottonseed meal (often found in cattle rations)	Avoid using in the diet of layers
Weak, thin or watery whites	Age of hens	Replace hens after 12 to 14 months of lay
	Ammonia from droppings	Better ventilation, use superphosphate on litter and manure and remove droppings regularly
	Increased alkalinity, (pH)-Loss of CO₂	Use a shell coating such as oil or refrigerated temperatures (40 to 55ºF)
	Respiratory diseases (Newcastle, infectious bronchitis and laryngotracheitis)	Follow a recommended program of vaccination and disease prevention in poultry
	Heredity	Select strains of known egg white (albumen) quality
	Arasan	Do not use arasan treated grains in the diet of layers
	Vanadium	Use sources of phosphorus in feeds known to have low amounts or none
	High environmental temperatures	Collect egg often (three to five times a day) and hold in refrigerated temperatures (40 to 55ºF)
	Sulfanilamide (sulfa drugs)	Use according to accepted recommendations
Flecks or spots in albumen	Partially cooked	Avoid excessive heat when washing eggs
	Blood and meat spots	Select strains known for clear egg whites (albumen)
Green rot and other type of microbial spoilage	Microorganisms, including bacteria, molds, and fungi	Maintain clean nesting material. Gather eggs frequently (three to five times a day). Use clean water for washing eggs. Maintain temperature of egg wash water (100 to 120ºF) above that of the egg at all times. Use recommended amounts of detergents and sanitizers. Keep equipment clean. Use clean packing material. Keep eggs refrigerated. Green rot is easily detected with an ultraviolet lamp candler. Other types of advanced spoilage are easily detected with regular candling techniques. Egg wash water containing 0.4 ppm of iron can promote bacterial spoilage.
Cloudy white	Prompt oiling of newly laid shell eggs	Delay oiling for one to six hours after eggs are laid.
	Prompt refrigeration of newly laid shell eggs at 32ºF	Keep eggs refrigerated below 45ºF
Off-odors and flavors	Chemicals for treating parasites. Odorous flowers, fruits, and vegetables in egg storage areas	Use chemicals recommended for lice and mite control. Do not use materials capable of imparting odors or flavors to eggs such as BHC, Lindane or Hexaphene. Do not store flowers, fruits and vegetables in the same area with eggs
Blood and meat spots	Hemorrhaging before and during ovulation	Tranquilizers, vitamins A and K, and aureomycin
	Breed	Select strains with low incidence
	Continuous intermittent periods of light	Use 14 hours of light
	Color or pogment caused by porphyrin as found in the brown shell egg	Select strains with low incidence

The Yolk

Condition	Causes	Corrective Measures
Olive- or salmon- colored yolks	5 percent or more cottonseed meal (found in some cattle diets)	Avoid its use in the diet of layers. Do not allow free-range poultry to consume spilled cattle feed
Platinum yolks (colorless yolks)	Possible infection (causative agent unknown)	Antibiotics (200 gm aureomycin and 2 lbs NF-180 per ton of feed for seven days)
Colorless yolks	Lack of xanthophyll	Consideration should be given to the source of xanthophyll such as yellow corn meal, alfalfa leaf meal, etc
Green yolks	100 to 250 mg of sodium chlorophyllin in feed	Avoid feeding to hens
	Seed pods of Shepperd's purse and pennycress	Use clean grains in feeding programs
Greenish-brown yolks	5 gm or more of pimento peppers daily to each hen	Use smaller amounts for a desirable color in the egg yolks
Orange-pink yolks	Red pepper	Avoid feeding to hens
Yellow to orange yolks	Seaweed meal (algae), dehydrated alfalfa meal, corn gluten meal, flower petal meal, dried chili peppers, powdered African red peppers, dried sweet potatoes, dried carrots, corn oil products, food grade fat soluble dyes, etc	Feed recommended levels of xanthophyll bearing materials for desired egg yolk color. Yellow= 13 mg of xanthophyll per lb of feed Medium orange= 23 mg of xanthophyll per lb of feed Orange= 34 mg of xanthophyll per lb of feed Maximum color will be present 10 days after the hens are placed on feeds for yolk color
Misplaced egg yolks	Large end up with yolk in large end - thin egg white and/or fat content of yolk. Large end up with yolk in small end - thin egg white and/or water content of yolk	Use accepted quality control practices while gathering and storing eggs in a cooled atmosphere
Blood and meat spots	Hemorrhages (ovarian, may be inherited)	Select strains with low incidence. Older breeds have approximately 30 percent blood spots in eggs
Mottled or blemished yolks	Nicarbazine	Do not feed to layers
	Cottonseed meal	Avoid feeding to layers
	Piperazine citrate	Do not use frquently or continuously
	Movement of water from egg white across vitelline membrane into yolk material	Cool eggs quickly and keep cool. Use other accepted quality control practices
Thick, pasty, rubbery or cheese-like	Crude cottonseed oil (malvalic acid and sterculic acid)	Avoid feeding to layers
	Yolks laid internally	Remove offending birds from the flock
Apparent misplaced egg yolk (observed in the whole egg by candling)	Unknown	The egg positioned with the small end down may help correct this situation
Off-odors and flavors	Chemicals for treating parasites. Odorous fruits and vegetables in egg storage area	Use of chemicals recommended for the lice and mite control. Do not use materials capable of imparting odors or flavors to eggs such as BHC, Lindane or Hexaphene. Do not store flowers, fruits, vegetables or petroleum products with eggs
	Chemicals or egg washing compounds	Do not place egg-washing powders or liquids directly on eggs
Flat	Weak vitelline membrane	Gather eggs often (three to five times a day). Maintain temperatures of 40 to 55ºF. Market often
Stuck yolks	Necastle disease	Use recommended vaccine
	Storage at high temperature	Store at 40 to 55ºF