Egg Bound and Genetics

[blklangshandude]

Is egg bound a nutritional issue or a biological issue? One of my fantasies is to create a chicken that is built to lay large eggs but actually lays small or medium eggs. The spirit is to create a breed or hybrid that isn’t susceptible to being egg bound. However I haven’t found any discussion on the internet as to whether this is a genetic issue or not. With my limited understanding of chickens I would assume egg laying breeds would be less likely to become egg bound as opposed to a dual purpose breed. I derive that logic because I hear overweight humans have a hard time giving birth. Dual purposes breeds are created with a focus on being bigger chickens rather than their egg laying capacity. The only eggbound chicken I ever had was an eight month old barred rock.

Is this even worth exploring or is this a nutritional issue or just a bad situation with no method of prevention? In my opinion this is the worst way to lose a chicken. They don’t die old or young. They die exactly at their prime of life. It is like a 25 year old human dying right as they have a good grasp on adulthood. It’s so tragic.

 

[nicalandia]

Is this even worth exploring or is this a nutritional issue or just a bad situation with no method of prevention?

This study revealed that heat stress (28.66%), asphyxia (23.23%), hypocalcemia (17.35%), salpingitis (7.54%), large size egg (6.18%), dehydration (5.73%) are the causes of Egg Bound Syndrome.

http://jwpr.science-line.com/attachments/article/24/J World's Poult Res 4(2) 30-36, 2014.pdf

 

[MrsEarthern]

With my limited understanding of chickens I would assume egg laying breeds would be less likely to become egg bound as opposed to a dual purpose breed.

From what I understand, egg laying breeds are more likely to become egg bound because they have been bred to lay eggs younger and more frequently.
Meat birds can also become egg bound due to genetic changes to body shape and rate of growth, basically the muscle can shift their inner bits around.
Heritage breeds and dual purpose breeds are less likely to become egg bound because they've had a little less interference from selective breeding in their physiology.

The reproductive system of chickens is a little wonky in that their inner bits don't necessarily connect, so being egg bound is similar to ectopic pregnancy in humans.
That said, I'm not sure this is something that could be fixed in the way you suggest, since egg size is related to mature adult size.

 

[Amer]

The bigger the chicken, the smaller the eggs compared to its body after a certain point. You don’t have to reinvent the wheel, just pick a heritage dual purpose breed and don’t let it get fat. A bird that doesn’t get egg bound is nothing special. You should select for wide and prominent pubic bones. Wide so eggs can easily pass and prominent because if they are not, that means your bird is fat. Pubic bones are on either side of the vent.

 

[JacinLarkwell]

I don't think its genetic. I've only had 1 egg bound bird. She lays awful eggs anyways, and the one that did get stuck was almost 3 times the normal size she had.