The simplest narrative for the domestication of the modern day chicken is that humans in southeastern Asia decided to tame some of the game birds in the area, which happened to be what we call red junglefowl, or Gallus gallus. Red junglefowl are a species of small pheasant that look remarkably similar to the brown leghorns which lay the majority of the white -shelled eggs that can be bought in grocery stores. 

Other species of junglefowl exist, including green and grey junglefowl, both of which also have the chicken shape but have plumage that bears no similarity to any domesticated chicken I’ve ever seen. The roosters of the green junglefowl have iridescent green almost scale-like feathers, and the roosters of grey junglefowl have spangling patterns that only cover necks and that lead into breast feathers that look like they belong on a vulturine guineafowl instead of a rooster.

Junglefowl are still considered pheasants (and by extension so are chickens), which also gets them lumped in with everything from peafowl of all sorts to ring-necks and golden pheasants, all of which are spectacular-looking and remarkably un-chickenlike in their own ways.