Bizarre olive egger genetics?

May 21, 2018
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Stillwater, OK
Hi All, we wanted to breed F1 olive eggers from a crested cream legbar hen last summer. First, we bred her to a red EE, pea combed F2 rooster and got two single combed, crested pullets. Two months later, we bred the same CCL hen to BCM rooster and got a black pullet with a single comb and a crest. The BCM and CCL were from a local breeder who shows and sells purebreds; CCL hen lays blue eggs. We wanted to figure out which pullet is laying which egg now that they all seem to be laying, so I set up a camera over the nest boxes. Of the two EE x CCL pullets, both lay tinted eggs. The BCM x CCL pullet lays a pink egg, see photo.

The EE roo who is the sire of the tinted egged pullets has a blue egg gene, because we also bred him to single combed tinted egg layer hens and got single combed pullets that lay tinted eggs and pea combed pullets that lay green eggs. So, EE rooster should be heterozygous for Blue and White egg shells. I guess the CCL hen must also be heterozygous for Blue and White egg shell, since none of her daughters lay Blue or Green eggs. Since Blue is dominant to White, their cross should give me 3/4 blue layers (one homozygous blue, two heterozygous blue/white) and 1/4 white (homozygous white). But using coin flip stats, the chance of all three out of three pullets being homozygous for White egg shell would be 1/4 X 1/4 X 1/4 = 1/64!!!! So, that could be what’s happened... But is there any other explanation? Any blue genes that are recessive to white or modifying genes that suppress blue? I’m going to keep watching those three pullets to confirm that they are laying the pink to tinted eggs that I think, but in the meantime, I’m so confused...
 

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May 21, 2018
1,888
4,848
436
Stillwater, OK
Hi All, we wanted to breed F1 olive eggers from a crested cream legbar hen last summer. First, we bred her to a red EE, pea combed F2 rooster and got two single combed, crested pullets. Two months later, we bred the same CCL hen to BCM rooster and got a black pullet with a single comb and a crest. The BCM and CCL were from a local breeder who shows and sells purebreds; CCL hen lays blue eggs. We wanted to figure out which pullet is laying which egg now that they all seem to be laying, so I set up a camera over the nest boxes. Of the two EE x CCL pullets, both lay tinted eggs. The BCM x CCL pullet lays a pink egg, see photo.

The EE roo who is the sire of the tinted egged pullets has a blue egg gene, because we also bred him to single combed tinted egg layer hens and got single combed pullets that lay tinted eggs and pea combed pullets that lay green eggs. So, EE rooster should be heterozygous for Blue and White egg shells. I guess the CCL hen must also be heterozygous for Blue and White egg shell, since none of her daughters lay Blue or Green eggs. Since Blue is dominant to White, their cross should give me 3/4 blue layers (one homozygous blue, two heterozygous blue/white) and 1/4 white (homozygous white). But using coin flip stats, the chance of all three out of three pullets being homozygous for White egg shell would be 1/4 X 1/4 X 1/4 = 1/64!!!! So, that could be what’s happened... But is there any other explanation? Any blue genes that are recessive to white or modifying genes that suppress blue? I’m going to keep watching those three pullets to confirm that they are laying the pink to tinted eggs that I think, but in the meantime, I’m so confused...
I was just thinking about this again and realized that my Punnets square proportion was off for the BCM x CCL. If the CCL is heterozygous, and the BCM has a white egg shell gene, the the last fraction would be 1/2, not 1/4. So, then the chances of getting only white shell genes from three pullets would be: 1/4 x 1/4 x 1/2 = 1/32.
 

The Moonshiner

Professional Chicken Tender
Nov 17, 2016
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A CCL hen should carry two genes for blue and pass one to all offspring. I don't know any way around that. Nothing would negate or cover the blue egg gene.
Your hen can not be pure for blue. With only having three of her pullets laying I would not count out that she carries one blue gene. Three is a small number to come to that conclusion IMO.
Seems you have a good understanding of what's going on. IDK so much now days but back years ago lots of people that crossing CCLs with brown leghorns would still result with CCLs. I would suspect something like that happened in her lines.
 
May 21, 2018
1,888
4,848
436
Stillwater, OK
A CCL hen should carry two genes for blue and pass one to all offspring. I don't know any way around that. Nothing would negate or cover the blue egg gene.
Your hen can not be pure for blue. With only having three of her pullets laying I would not count out that she carries one blue gene. Three is a small number to come to that conclusion IMO.
Seems you have a good understanding of what's going on. IDK so much now days but back years ago lots of people that crossing CCLs with brown leghorns would still result with CCLs. I would suspect something like that happened in her lines.
Yeah, it’s really disappointing that our one surviving CCL does not have two blue egg shell genes. We do have Ameraucana pullets, so I guess we will try those for breeding OEs. It just seems like such bad luck that our blue egg layer has not thrown a blue laying pullet, that I thought I’d see if anyone has any additional insights.
 
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