Most Poultry Shows are regulated by The Poultry Club of Great Britain in the UK.
These shows must comply with the PCGB rules.  It is the Breed Clubs who determine what classes should be included for a show.  More details of the Poultry Club of Great Britain show rules can be found at:

June 2016

1-4th Royal Bath & West       
11th  Arun Valley Poultry Fanciers
19th North Yorkshire County Show
21st Royal Cheshire Agricultural Society
25/26th Royal Highland Show, Edinburgh
29/30th Royal Norfolk Show
  Royal Cornwall Show
  Stithians Agricultural Show
  Driffield Agricultural Show
  Royal Highland Show
  Northumberland County Show

July 2016

27th Nantwich & Sth Cheshire Agricultural Show
30/31st      East of England Poultry Club, Heckington
  Carnwath Agricultural Show
  Salisbury Show