WEBVTT - What's the Difference Between Eggs of Different Colors? 0:00:02.040 --> 0:00:07.080 Welcome to brain Stuff from How Stuff Works, Hi brain Stuff, 0:00:07.160 --> 0:00:10.080 Lauren vocal Bomb. Here Peru's the egg section of a 0:00:10.080 --> 0:00:12.959 grocery store of Farmer's Market, and you'll notice cartaons of 0:00:13.000 --> 0:00:16.840 eggs separated into white and brown, and sometimes even green 0:00:16.920 --> 0:00:19.560 or blue eggs. But once they arrive scrambled on a 0:00:19.600 --> 0:00:21.880 plate or baked into a cake, it's tough to tell 0:00:21.880 --> 0:00:24.959 the difference. So what is the difference between eggs with 0:00:25.000 --> 0:00:28.600 shells of different colors? This isn't a situation like rice 0:00:28.720 --> 0:00:31.560 or flour. Brown eggs are not more natural, and white 0:00:31.560 --> 0:00:34.880 eggs have not been dcolored with bleach. Both varieties occur 0:00:35.000 --> 0:00:39.040 completely naturally, as do bluish green chicken eggs. But really 0:00:39.280 --> 0:00:41.760 all chicken eggs are the same on the inside. So 0:00:41.840 --> 0:00:44.840 what causes different egg colors among the same type of bird. 0:00:45.640 --> 0:00:49.279 We spoke with Dr Justin Fowler. We cannot make this up, 0:00:49.520 --> 0:00:53.400 Who's a professor at the University of George's Poultry science department. 0:00:53.800 --> 0:00:56.920 He said, the different colors, or the presence of spots 0:00:57.000 --> 0:00:59.760 or speckling, come down to the genetics of the bird. 0:01:00.320 --> 0:01:02.800 Leghorn chickens, which make up most of the commercial egg 0:01:02.800 --> 0:01:06.080 industry in the United States lay white eggs, while Orphington's 0:01:06.160 --> 0:01:09.520 or plymouth rocks will lay brown eggs. The Amerquana breed 0:01:09.560 --> 0:01:12.280 has a pigment that's able to permeate the whole egg 0:01:12.360 --> 0:01:14.959 shell and make blue colored eggs that are colored on 0:01:15.000 --> 0:01:18.440 both the inside and outside of the shell. So there 0:01:18.440 --> 0:01:21.160 you go. I want to know whether a specific chicken 0:01:21.200 --> 0:01:23.280 will pop out a white egg or a colored egg. 0:01:23.360 --> 0:01:27.560 Examine the chicken's earlobe. Surprise, birds have ear lobes more 0:01:27.600 --> 0:01:30.399 often than not. Chickens with white or lighter ear lobes 0:01:30.440 --> 0:01:33.520 tend to have white feathers and thus white eggs, while 0:01:33.560 --> 0:01:36.240 those with colored feathers and ear lobes tend to produce 0:01:36.360 --> 0:01:40.399 colored eggs. Where does this color come from? Though, Here's 0:01:40.440 --> 0:01:43.480 where Understanding how an egg comes to be is important. 0:01:43.880 --> 0:01:47.520 Chicken yolks or ova form in the chickens ovaries. A 0:01:47.600 --> 0:01:50.480 fully formed ovum will leave the ovary and be deposited 0:01:50.480 --> 0:01:53.960 into the oviduct. This part of the chicken's reproductive system 0:01:54.000 --> 0:01:57.840 has five distinct sequential segments which the yolk passes through 0:01:57.880 --> 0:01:59.960 on its way to the outside world. But it's the 0:02:00.040 --> 0:02:02.960 fourth one, the shell gland, that affects the color of 0:02:03.000 --> 0:02:06.560 the egg. This is where the shell forms around the ovum. 0:02:06.680 --> 0:02:10.040 Fowler explained the process. He said, the shell of all 0:02:10.120 --> 0:02:13.280 chicken eggs are made of calcium carbonate, a crystal that's 0:02:13.280 --> 0:02:16.160 white in color. So all eggs are at least at 0:02:16.200 --> 0:02:19.240 the start white. Any that we then see that our 0:02:19.280 --> 0:02:21.799 other colors have had a pigment deposited on them as 0:02:21.840 --> 0:02:24.440 they were moving through the overduct, after the white egg 0:02:24.440 --> 0:02:26.920 shell had been deposited. You can see this if you 0:02:26.960 --> 0:02:28.840 open up a brown egg and look at the inside 0:02:28.840 --> 0:02:32.760 of the shell, it'll be white. Two pigments are responsible 0:02:32.760 --> 0:02:35.799 for the spectrum of chicken egg color. Shades of greens 0:02:35.800 --> 0:02:38.160 and blues are caused by the pigment bill of vert in, 0:02:38.360 --> 0:02:42.840 while protoporphyrin is responsible for reddish brown hues. The same 0:02:42.919 --> 0:02:46.280 egg coloring process holds true for all birds with colorful eggs. 0:02:46.560 --> 0:02:50.680 American robin eggs, for instance, are famously blue. Oh but 0:02:50.840 --> 0:02:53.120 that egg inside an egg story that you might have 0:02:53.120 --> 0:02:56.280 seen going around the internet, that's another thing entirely, and 0:02:56.400 --> 0:03:01.000 involves an egg accidentally reversing its course in the oviduct. Meanwhile, 0:03:01.160 --> 0:03:04.239 we'll leave you with the answer to a practical egg query. 0:03:04.680 --> 0:03:07.960 Should chicken eggs be kept refrigerated or at room temperature. 0:03:08.639 --> 0:03:11.640 It depends on whether you live in a country Australia, Japan, 0:03:11.680 --> 0:03:14.600 and the United States, for instance, that requires eggs produced 0:03:14.639 --> 0:03:18.760 for commercial sale to be washed. This protects against salmonella, 0:03:18.960 --> 0:03:22.120 but also removes a waxy shell coating that naturally defends 0:03:22.160 --> 0:03:31.760 eggs against micro organisms, thereby necessitating refrigeration. Today's episode was 0:03:31.800 --> 0:03:34.800 written by Christopher Hassiotis and produced by Tristan McNeil and 0:03:34.880 --> 0:03:37.360 Tyler Clang. For more on this and lots of other 0:03:37.400 --> 0:03:52.320 foul topics, visit our home planet, how stuff Works dot com.