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Alternatives to conventional and enriched cage systems

109. These systems include deep litter, perchery, aviary and free range. They provide various degrees of freedom of movement and facilities to encourage normal behaviours but at the cost of large group sizes and the increased likelihood of injurious pecking and cannibalism.

110. In 1991 the Council published its Report on the Welfare of Laying Hens in Colony Systems. We stand by the majority of recommendations in that report. Nonetheless, we believe that the industry has developed and improved systems since then and we wish to update a small number of the recommendations on the basis of recent information about best industry practice.


111. We urge the Government to pursue implementation of recommendations made in the Report on the Welfare of Hens in Colony Systems (1991) and accepted in the Government response for implementation on an EU basis (some of these are modified in the following paragraphs). The forthcoming EU review offers an ideal opportunity to do this.

Nest boxes

112. Sufficient individual or communal nest boxes should be provided in colony systems to allow daily access for all hens.


113. Best practice within the industry would suggest that individual nest boxes should be provided at a rate of at least one for every five or six hens and that communal nest boxes should be provided at a maximum rate of 120 birds/mē of nest box area, dependent on well designed nest boxes and the appropriate strain of bird.

Perching space

114. In the various non-cage systems currently in use, hens need 15cm of perch length (dependent on their size and the system) in order that all birds may perch at the same time. More perch length is required in non-cage systems than in enriched battery cages because of increased competition.


115. We recommend a minimum perching allocation of 15cm length per hen in non-cage systems, provided that the system design allows easy perch access.

Feed and water supplies

116. We continue to stress the need for sufficient feeders and drinkers to enable all hens to obtain adequate feed and water and so meet the requirements of the Welfare of Livestock Regulations 1994.


117. We accept industry best practice and recommend allowing a maximum of 100 hens per standard bell-type drinker or 10 birds per nipple or cup drinker.

118. We re-iterate our earlier recommendation for a minimum provision of 10cm of linear feed trough length per hen (i.e. 5cm each side). We also now recommend at least 4cm per hen of the perimeter when circular feeders are used.

Flock or colony size

119. We believed in 1991 that a flock size of a maximum of 2000 was realistic. This figure was not accepted then by Government and in 1997 we have no clearer evidence of what the figure should be. There is commercial experience to suggest that larger group sizes can operate satisfactorily.


120. Research is needed to establish optimum flock sizes for laying hens.

Deep litter

121. These are flock systems in which the hens are confined to a building with access to an area littered with material such as wood shavings or straw. A raised, perforated floor is often incorporated. The accommodation is usually in a building with a controlled environment. The EC Egg Marketing Regulations state that the maximum stocking density should be 7 birds/mē. This was the figure recommended in our 1991 Report.

122. Deep litter summary assessment:


  • Varied physical environment and an opportunity to express a wide range of behaviours.
  • No exposure to predators.
  • Freedom to move within the house.
  • Provision of nest boxes, perches and dust bathing facilities is relatively easy.
  • Easier to inspect birds than in cage systems.
  • Improved bone strength due to increased activity.
  • Can be combined with access to range.
  • Light level and period easily controlled throughout the year.


  • Beak trimming may be required.
  • Large colony size increases risk of social disharmony.
  • If feather pecking or cannibalism occur, control may be difficult.
  • Increased risk of endoparasites and ectoparasites due to access to droppings.
  • Disinfection and disinfestation may be difficult following depopulation.
  • Stocking density is sometimes insufficient to achieve optimum temperature range under cold ambient conditions.
  • Management of litter may be difficult during winter months.

Perchery and aviary systems

123. These are usually floor based with tiers of floors or perches at several levels, sometimes with an area of litter on the floor. Feed, water and nesting accommodation are located at more than one level. The systems are normally in controlled environment buildings.

124. The Report on the Welfare of Laying Hens in Colony Systems (1991) recommended that hens in perchery or aviary systems should be stocked at no more than 15.5 hens/mē. This has subsequently become industry practice and appears to work well.

125. Perchery and aviary systems summary assessment:

Pros: As for deep litter systems plus;

  • Provision of perches and other facilities at different heights which allow a greater use of space.
  • Higher stocking densities make temperature control easier in cold weather.
  • Birds can escape aggression by moving within the house.

Cons: As for deep litter systems plus;

  • Furniture structures in the house may impede observation and inspection.
  • Hens can be injured by falling between levels or flying into furniture.
  • Birds can become soiled from above unless manure belts are provided or perches are placed carefully.
  • Difficult to depopulate.
  • High risk of injurious feather pecking and cannibalism, thus beak trimming is often necessary.

Free range systems

126. Hens can be housed on deep litter or in perchery or aviary systems and the EC Egg Marketing Regulations state they must further be provided with continuous day time access to land mainly covered with vegetation.

127. Free range summary assessment:

Pros: As for perchery and aviary systems plus;

  • Freedom to access the range area and thus express a wide behavioural repertoire.
  • Opportunity to graze on vegetation and to augment and vary diet.
  • Opportunity to dust bath in soil.

Cons: As for perchery and aviary systems plus;

  • Predation or fear of predation may be a problem.
  • When outside, birds may suffer discomfort due to climatic extremes.
  • Large pop holes can adversely affect environmental conditions within the house.
  • Disease risk due to access to droppings and contact with wild birds.
  • Beak trimming is essential because of group sizes and high levels of natural light.
  • Pasture management is an additional requirement.


128. For free range hens, we recommend that the maximum stocking density of 1000 birds per hectare is maintained. We agree with industry practice that a maximum distance of 350 m from the poultry building should be allowed for the purpose of calculating the total number of birds that may be kept in an enclosure.

129. It is important to establish a system of rotation of grazing or house movement in order to prevent poaching and build up of disease.