The Great SI (Shape index) experiment

SiriusChicken

Songster
Apr 22, 2017
111
89
107
Willow Creek, CA
Update: All 3 Gold Laced cross chicks are cockerels. After reviewing written notes at hatch I think the dead chick was Silver Laced (tiny & gray with gray legs & the SL egg was tiny). It must’ve crawled onto the wrong shell. The 3 cockerels are all more gold than the others, had gold legs at hatch, & all were fast feathering.

English Orpingtons are slow feathering so cockerels should be slow feathering like mom. Both SL were slow feathering but I checked baby pics & the Gold Laced was much faster feathering than the others, sexual dimorphism or some such thing.

Incidentally the GL is also the one with all long pointy eggs with lower SI values.

Also of note that the Silver Laced (Rezz) with wider shorter eggs with the highest range of SI values produced 6 live females & 1 dead female.

It appears unlikely that each hen has a range of SI with higher SI values being female & lower SI being males. It seems more likely it’s either a natural bias of sex per hen, or in general the higher SI value eggs have higher probabilities of being female, independent of hen, which would be good news for hatcheries if they had a scanner that only accepted SI values over 80. The study only took SI values over 78. In my test the females were all of a SI value of 80 or higher except for the Barred Rock. Will post individual egg SI info in a bit.

Needs more scientific studying to prove either way.
 

SiriusChicken

Songster
Apr 22, 2017
111
89
107
Willow Creek, CA
Individual Egg Information:

(Rounded to 1 decimal point)

05/24, SL, 57.5g, SI 83.9 = Female
05/25, SL, 57.6g, SI 83.7 = Female
05/27, SL, 59.5g, SI 82.9 = Female
05/28, SL, 61.2g, SI 80.5 = Female (died hatching)
05/30, SL, 60.1g, SI 80.6 = Female
06/10, SL, 59.2g, SI 81.9 = Female
06/11, SL, 58.0g, SI 82.0 = Female
05/26, GL, 61g, SI 77.8 = Male
05/31, GL, 59.0g, SI 77.8 = Male?
05/07, GL, 60.3g, SI 77.8 = Male
05/27, SL, 52.6g, SI 80 = Female (died after hatch)
05/31, BR, 59.6g, SI 76.7 = Female
06/07, BR, 60.3g, SI 76.7 = Male

Total SL 9/9 female 100%, GL 0/3 female 0%, BR 1/2 female 50%.

Orpington cross 8/11 female 73%,
BarredRock cross 1/2 female 50%
Total all chicks: 9/13 female = 69%

All females SI values of 80 or higher except for the BarredRock/Dominique cross.
 
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