A white feather has been a traditional symbol of cowardice, used and recognised especially within the British Army and in countries of the British Empire since the 18th century, especially by patriotic groups, including some early feminists, in order to shame men who were not soldiers. It also carries opposite meanings, however: in some cases of pacifism, and in the United States, of extraordinary bravery and excellence in combat marksmanship.
As a symbol of cowardice, the white feather supposedly comes from cockfighting and the belief that a cockerel sporting a white feather in its tail is likely to be a poor fighter. Pure-breed gamecocks do not show white feathers, so its presence indicates that the cockerel is an inferior cross-breed.
In August 1914, at the start of the First World War, Admiral Charles Fitzgerald founded the Order of the White Feather with support from the prominent author Mrs Humphrey Ward. The organization aimed to shame men into enlisting in the British army by persuading women to present them with a white feather if they were not wearing a uniform.
This was joined by some prominent feminists and suffragettes of the time, such as Emmeline Pankhurst and her daughter Christabel. They, in addition to handing out the feathers, also lobbied to institute an involuntary universal draft, which included those who lacked votes due to being too young or not owning property.
While the true effectiveness of the campaign is impossible to judge, it did spread throughout several other nations in the Empire. In Britain it started to cause problems for the government when public servants and men in essential occupations came under pressure to enlist. This prompted the Home Secretary, Reginald McKenna, to issue employees in state industries with lapel badges reading "King and Country" to indicate that they too were serving the war effort. Likewise, the Silver War Badge, given to service personnel who had been honourably discharged due to wounds or sickness, was first issued in September 1916 to prevent veterans from being challenged for not wearing uniform. Anecdotes from the period indicates that the campaign was not popular amongst soldiers - not least because soldiers who were home on leave could find themselves presented with the feathers.