Hi Brian,
It is commonly assumed that the association between French people and the rooster as a symbol stems from the fact that in Latin, the word gallus means both "rooster" (or chicken, which is less glorious; ref. the ongoing current debate on the forum...) and "gaulois", the name of the inhabitants of France (la Gaule) in the antiquity. As a symbol of France, the rooster is pictured here and there from the middle ages and even before. This usage has increased during the French revolution (1789) but then Napoleon substituted the eagle to the rooster. The rooster returned during the 1830 revolution and was re-adopted as a symbol by the "Monarchie de Juillet".
The rooster has never been the official symbol of France though, although it has often been used to picture the French (WWI: remember all the propaganda pictures showing the French rooster fighting - and defeating - the Prussian eagle), and still is, notably by sport teams.
