ArticleScientific reports2021
Laying hen mortality in different indoor housing systems: a meta-analysis of data from commercial farms in 16 countries.
Article in Scientific reports, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
15 citing papers in PubMed, 56 citations in OpenAlex.
- Understanding the tradeoffs between quality and morality: Insights from consumer response to animal welfare eggs in China.Poultry science · 2026Article
- The right fit: A decision tree to select a protocol for assessing the welfare of laying hens.Poultry science · 2025Review
- Maximum vertical height during wing flapping of laying hens captured with a depth camera.PloS one · 2025Article
- From cages to cage-free: A qualitative exploration of Chinese egg producers' views on the opportunities and challenges to adopting cage-free egg production systems in China.Animal welfare (South Mimms, England) · 2025Article
- The Effect of Rearing and Adult Environment on HPA Axis Responsivity and Plumage Condition in Laying Hens.Animals : an open access journal from MDPI · 2024Article
- Egg Quality, Yolk Fatty Acid Profiles from Laying Hens Housed in Conventional Cage and Cage-Free Production Systems in the Andean Tropics.Animals : an open access journal from MDPI · 2024Article
- Mind the ramp: Association between early life ramp use and spatial cognition in laying hen pullets.PloS one · 2024Article
- Low Ca diet leads to increased Ca retention by changing the gut flora and ileal pH value in laying hens.Animal nutrition (Zhongguo xu mu shou yi xue hui) · 2023Article
- Identification of reference genes for expression studies in the liver and spleen of laying hens housed in cage and cage-free systems.Open veterinary journal · 2023Article
- Improving hen welfare on cage-free egg farms in Asia: Egg producers' perspectives.Animal welfare (South Mimms, England) · 2023Article
- Practical Application of the Five Domains Animal Welfare Framework for Supply Food Animal Chain Managers.Animals : an open access journal from MDPI · 2022Article
- Cage egg producers' perspectives on the adoption of cage-free systems in China, Japan, Indonesia, Malaysia, Philippines, and Thailand.Frontiers in veterinary science · 2022Article
- Productivity of mother pigs is lower, and mortality greater, in countries that still confine them in gestation crates.F1000Research · 2022Article
- Comparison of Behavioral Time Budget and Welfare Indicators in Two Local Laying Hen Genotypes (Atak-S and Atabey) in a Free-Range System.Animals : an open access journal from MDPI · 2021Article
- "Mothers Should Have Freedom of Movement"-Citizens' Attitudes Regarding Farrowing Housing Systems for Sows and Their Piglets.Animals : an open access journal from MDPI · 2021Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Societal concern with the welfare of egg laying hens housed in conventional cages is fostering a transition towards cage-free systems in many countries. However, although cage-free facilities enable hens to move freely and express natural behaviours, concerns have also been raised over the possibility that cage-free flocks experience higher mortality, potentially compromising some aspects of their welfare. To investigate this possibility, we conducted a large meta-analysis of laying hen mortality in conventional cages, furnished cages and cage-free aviaries using data from 6040 commercial flocks and 176 million hens from 16 countries. We show that except for conventional cages, mortality gradually drops as experience with each system builds up: since 2000, each year of experience with cage-free aviaries was associated with a 0.35-0.65% average drop in cumulative mortality, with no differences in mortality between caged and cage-free systems in more recent years. As management knowledge evolves and genetics are optimized, new producers transitioning to cage-free housing may experience even faster rates of decline. Our results speak against the notion that mortality is inherently higher in cage-free production and illustrate the importance of considering the degree of maturity of production systems in any investigations of farm animal health, behaviour and welfare.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.