1. The genus name for chickens and other fowl that descended from the red jungle fowl is Gallus. Roosters wake you up, like coffee wakes you up. Sure, we could just name ourselves "rooster", just like we could say "wake you up," but we are nerds.
2. The word "gallus" means "cocky," "bold," or "daring" in Scots. Coffee is all those things in liquid form. Again, we could have named the coffee "cocky," "bold," or "daring," but that's not how we roll.
3. During the "Gangs of New York" period in New York in the 1860s there were several badass warrior women who gained notoriety for their gallus exploits, including Hellcat Maggie, Sadie the Goat, and Gallus Mag. Mag was a six-foot-tall banshee of a woman who worked as a bouncer at a bar and famously bit an ear off any man that she forcibly removed from her bar and kept them (the ears) on display in a jar of alcohol. This in no way relates to specialty coffee roasting, but we admire her panache and dedication to craft, so maybe it relates in that way? Regardless, it's another way that the name Gallus is interesting. So there you are.