Oviposition
I decided to research the study that proved the rotation of the egg and I'm glad I did. I thought that they rotated vertically, assuming there is more soft space that way than horizontally which would run into the hips. I think that is exactly what happened to
@RebeccaBoyd hen today. The narrow point of the egg poked out and limited rotation of her leg, otherwise it would hurt and perhaps she even knew she might break the egg. As soon as the rotation was done she wanted it out. I'm not certain if the rotation was early or late but I'm leaning towards early as Rebccaboyd did not think egg laying was the issue initially. Therefore it could not have been that far down the tracks.
For those who have not heard of this before:
The egg rotates prior to being laid in a process called oviposition so that the large end comes out first. The oviposition, is regulated by several hormones (oxytocin, arginine-vasotocin and prostaglandines). This hormone surge causes the fully formed egg to go through a 180-degree rotation. It is this rotation that causes the egg to be pushed into the vagina. Bradfield (1951) using X-rays found that hen eggs do rotate 180° within the uterus in a horizontal plane about an hour before laying and in 9 of the 10 hens he studied eggs were laid blunt end first in a lab environment.
@bgmathteach @Ribh @LozzyR @Aussie-Chookmum @MaryJanet @Shadrach @Marie2020 @micstrachan @ChicoryBlue