Overstocking, Overcrowding, Excessi ...

Overstocking, Overcrowding, Excessive Density of Laying Hens

Overstocking, Overcrowding, Excessive Density of Laying Hens

While studying the subject, scientists rapidly determined that reducing the space allowance for each bird had many negative effects: Increase mortality, decreased hen-day egg production, decreased hen-housed egg production, more egg breakage, increased the number of floor eggs, and reduced net profit per bird, variable effects on total farm profits. Likewise, the reduction of feed space per hen will reduce the feed consumption and the performance will be affected.  In barn/or free-range system, the litter condition may be deteriorated. Lack of sufficient nest space will increase the numbers of floor eggs.

In most cases, stocking hens too densely result in a drop in egg production; an increase in the number of cracked eggs, hairline cracks, and ridged waist (body check) defects, misshapen and feather loss and pecking behaviour.

It has been shown that a significantly higher rate of body-checked eggs are produced during the first two hours of the day in high density when compared to low-density cages, and when the lights are turned off later versus earlier in the evening.

The key to success is ultimately to identify the relationship between capital costs, production costs, returns and bird welfare for each flock. One important element in this relationship is that of stocking density- the number of birds placed into a given area. Production per bird tends to remain constant until flock size reaches a certain number. As this number is increased above what could be called the maximum stocking density, mortality will increase and production will probably decrease. The losses associated with this per bird production decrease will initially be more than compensated for by the increased total production from the house from the increase in the number of birds.

As the number of birds has further increased a point is reached when production losses from higher mortality and lower per bird production are so great that the increased total house population cannot compensate for them. There is a point before this where modern society will not accept the conditions that are considered inferior caused by increasing the number of birds. The successful manager will take all of these factors into consideration and house the maximum number of birds without reaching a population density that has poor consequences. Therefore it is important for managers to be aware of regulations regarding stocking densities and cage sizes

Observed Clinical Signs Happenings

Egg drop

  • Egg production drops gradually
  • Decreased hen-day egg production
  • Decreased hen-housed egg production



  • Low mortality or increases gradually


Dead birds

  • Poor bodily  condition


Flock Behaviour Pattern

  • Decreased flock mobility or activity
  • A higher rate of feather pulling or eating
  • A higher rate of feather pecking
  • Feather pecking is a behaviour expressed by dominant birds at subordinates


  • Poor feather cover or feather loss
  • Feather pulling or eating
  • Feather pecking
  • Feather pecking is a behaviour expressed by dominant birds at subordinates

Feed Consumption

  • Feed intake reduced
  • the reduction of feed space per hen will reduce the feed consumption and the performance will be affected

Shell quality

  • More egg breakage
  • Increase in the number of cracked eggs,
  • Increase hairline cracks
  • Increase ridged waist (body check) defects
  • Increase misshapen egg.
  • increase the numbers of floor eggs, In barn/or free-range or aviary systems

Overstocking, Overcrowding, Excessive Density of Laying Hens DOES NOT show or exhibit or manifest any of the following clinical signs happenings:

  • Egg production declines rapidly
  • High mortality or increases rapidly
  • Dead birds: Good bodily condition
  • Visibly sick birds
  • Droppings abnormalities
  • Respiratory abnormalities
  • Neurological Nervous
  • Lameness or unusual movements, incoordination, ataxia
  • Eyes abnormalities
  • Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
  • Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
  • Feed Consumption Changes
  • Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
  • Internal Egg quality
Causing Agents
Insufficient Equipment and Space requirements
Affected Systems/Organs
Mainly Affects
Egg production, Egg Quality. Liveability
Reduce bird density. Crowding increases egg breakage. It maybe that an excessive number of cracked eggs will offset some of the additional income resulting from more birds per cage
Suggested Actions
  • Can be dealt with in house
  • Technical assistance recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 1149

Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition. page 98, 1017, 1046, 1098

Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. page 29

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