Here's a fun fact: did you know that roosters are omnivores? Yes, they  will eat just about anything. Another fun fact: roosters are mean and  more often than not aggressive, so they do not have friends, even among  other roosters and hens. So why would a country choose a rooster as  their symbol? 

References: 

https://www.vdio.com/gallic-rooster-national-bird-france/ https://www.chickenboy.com/ https://en.wikipedia.org/wiki/French_Community_of_Belgium https://animals.mom.com/functions-wattles-chickens-5568.html https://blog.cacklehatchery.com/why-does-a-rooster-have-wattles/ https://roadstothegreatwar-ww1.blogspot.com/2014/11/about-those-chickens-in-france.html https://www.dar.org/archives/dar-support-initiatives-during-world-war-one https://en.wikipedia.org/wiki/Charleroi_Red_Roosters https://nationaldaycalendar.com/days-2/national-coq-au-vin-day-may-29/ https://www.discovermagazine.com/planet-earth/roosters-have-special-ears-so-they-dont-crow-themselves-to-deaf https://theorganicgoatlady.com/7-reasons-not-rooster/ https://en.wikipedia.org/wiki/French_Community_of_Belgium