Article Text

Download PDFPDF
Poultry Production
Unusual eggshell defects in a free-range layer flock in Great Britain
  1. B. W. Strugnell1,
  2. P. McMullin2,
  3. A. M. Wood3,
  4. R. A. J. Nicholas4,
  5. R. Ayling4 and
  6. R. M. Irvine5
  1. AHVLA – Thirsk, West House, Station Road, Thirsk, North Yorkshire YO7 1PZ
  2. Poultry Health Services, Main Site Lane, Dalton, Thirsk, North Yorkshire YO7 3JA
  3. AHVLA – Lasswade, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ
  4. Mycoplasma Group, AHVLA – Weybridge, New Haw, Addlestone, Surrey KT15 3NB
  5. AHVLA – Luddington, Stratford-upon-Avon, Warwickshire CV37 9SJ
  1. e-mail: ben.strugnell{at}

Statistics from

WE wish to report the occurrence and investigation of unusual eggshell defects in a flock of 14,000 free-range layer hens in England. The eggshell defects, associated pattern of reduced egg production and pathological features closely resembled reports from the Netherlands (Feberwee and others 2009a) and Italy (Catania and others 2010) for which the term ‘eggshell apex abnormalities’ (EAA) has been used. In addition to the field cases described in Europe, recent experimental studies have reproduced the condition by sequential inoculation of specific pathogen-free chickens with infectious bronchitis virus (IBV) and strains of Mycoplasma synoviae, isolated from the reproductive tracts of birds displaying EAA lesions in the field (Feberwee and others 2009a, Feberwee and Landman 2010), and reasonable protection has been demonstrated with a live M synoviae vaccine (Feberwee and others 2009b). One hypothesis is that certain strains of M synoviae, under particular circumstances, display a tropism for the hen's reproductive tract, where colonisation leads to the production of abnormal eggs with …

View Full Text

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.