This is not taken from the comic but when you know this about turkeys it makes sense:
"The wild turkey's bald head can change color in seconds with excitement or emotion. The birds' heads can be red, pink, white or blue."
Fun fact! The exposed skin that changes color based on mood is a trait of both turkeys and cranes. The joke just keeps on going.
Updated
...? What's the matter, Shoukaku-nee?What should I do, Shoukaku-nee...!...She is a turkey after all, isn't she...Who said "turkey" just now in this room?This orange is sweet!Who said turkey!?Senpai is really furious!The skin color of a turkey's head...Yukikaze was the one who chose the oranges when we bought them!...Is that so? I'm sure that someone is gossiping about me...You sure have guts, 5th CarDiv...I was looking for you!Crap, I had forgotten...Isn't that great? Good work!Ah, so you are here, Zuikaku!You're skipping today's training with the 1st CarDiv, right?Really, don't joke around...!...Hey.It seems like from this fact is why turkey is called "Seven Head Bird".
Japanese for turkey is 七面鳥, which literally means "seven", "face", and "bird" for each kanji.Heeee.....TELEVISIONI didn't say it, I didn't! It must be your imagination...Will change depending on its excitement, such as Red, Blue, or Purple.