And for those that know animals are color blind: Birds aren't. Chickens can see colors at least as well as we can. There are a few dog training schools that have students click train chickens to peck only at a certain color as an exercise, and they pick up on it really fast. Not only do my chickens love red, my cockatiel does too.
Red and bright shades of orange are a distinct NO-NO here with one of my roos! I was working in the yard one day, and had put a red bandana on my head. Forgot all about it when I went to feed the chickens. The roo in question, flew at me like I was an intruder, feet first!
I walk with a cane, so bumped him in mid air. He landed and came back THREE times more, and with a vengence! Not a good thing to have a 9lb roo, with spurs, 2 feet from your face. Six other roos in the pen, and no one else reacted this way, nor did any of the hens. It dawned on me when I got back in the house that I still had it on. Blaze orange will set him off too. He reacts like I am a large, strange rooster coming into his territory. Funny thing is, he is the lowest of the low in the pecking order. Needless to say, I don't wear red or orange...at least not around him.
We had a bantum rooster that would attack anything red including Grandma's polyester pant suit. Love that memory! There she is walking up the sidewalk and there's Buster charging at her, making quite a racket and grabbing her pant cuff. Hmmm. might have to get some bantums as a security force.