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You can determine the colour of an egg a chicken lays by looking at it's earlobe

Wait. Chickens have earlobes?!

Yes, that's right. Chickens do have ears although they are hidden by the feathers on the side of the head. But when the feathers are pushed aside, the openings that serve as ears appear. There is no outer ear, such as we humans have, but chickens do have earlobes which can be clearly seen. The colour of the lobe varies with the breed of the chicken, ranging from white to almost black. Chickens with white earlobes lay white eggs exclusively while birds with dark lobes lay brown eggs. The fascinating Araucana breed of chickens can even have earlobes that are a pale green or blue colour. Sure enough, they lay eggs of the corresponding hue. It appears that the same gene that determines the colour of the earlobe also determines the colour of the egg. The colour itself is determined by the presence of porphyrins which occur once hemoglobin, the oxygen-transporting molecule found in red blood cells, is broken down. This whole process is controlled by genetics, which means the colour of the eggs is under genetic control.


@JoeSchwarcz

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