Zane Oberholzer

13 karmaJoined


Dear Effective Altruism community,

It is my great pleasure to announce that this project has been fully funded.

A huge thank you to everybody who backed, shared, and showed interest!

If you are interested in following the developments/findings of the project, I will be posting lab notes on Experiment's platform (link: here).

So the project is not looking to target the genes that code for egg-laying. We are testing regulatory sequences for their ability to selectively suppress the expression of the gene DMRT1 in gonadal tissue, resulting in the development of ovaries instead of testes. In other words, we are causing male-to-female sex reversal by targeting a single gene: DMRT1. There is the possibility, however, that a gene on the W chromosome either promotes ovary development or ovulation. We do not know this for certain.

The genetics of eggshell colour hasn't fully been elucidated. It involves several pigments and enzymes but the genes encoding them haven't been functionally tested and it's still uncertain how the pigments are synthesized, transported etc. So I think this approach would be very cumbersome and challenging.

But I do agree, pursing a more straightforward solution will have the greatest chances of success.

Well these are two different problems: 1). The practice of male chick culling and 2). The treatment of laying hens.

Although these two problems are linked, I don't think  it's fair to say "it's better to kill day-old male chicks than allowing them to live horrible lives in cages". Both problems are equally grotesque and require intervention. 

I think that both problems have "gone under the radar" so if they were discussed more and given more public attention, it will prompt other researchers to look into alternatives and solutions. 

1. The various in-ovo sexing technologies to find the male eggs and destroy them before they hatch- Respeggt eggs are already available for sale in Germany, France, and The Netherlands and Open Phil has funded the Egg-Tech prize

The company  respeggt GmbH has two projects:

  1. Seleggt’s in-ovo sexing technology is similar to a gender test. Allantoic fluid from eggs is extracted and the hormone content is analysed for sex-specific differences. The drawback is that the technology requires expensive machinery and currently the technology cannot meet industrial demands. This technology is also not very suitable for small scale hatcheries. Another consideration is that males can only be sexed after 9 days of incubation. Indeed, this is an improvement over culling day-old male chicks but male chicks are still being produced so it only saves part of the time investment and there will still be costs involved in disposing of the males.
  2. Respeggt GmbH’s second project pledges to hatch the male chicks that are part  of the Seleggt project. These chicks are reared alongside the female chicks. This “dual-purpose” approach is unfortunately not financially viable for every hatchery to adopt.


2. Change the sex of the embryo in the egg  https://www.google.com/amp/s/amp.theguardian.com/food/2021/jan/31/good-vibrations-sound-waves-eggs-ethical-slaughter-male-chicks

This looks like a very interesting technology! I wish there was more information available on how it works. Their technology (SOOS) uses a combination of environmental factors including sound waves to induce male-to-female sex reversal in the egg. A couple of questions I have about their technology though is whether the sex reversal persists into adulthood and whether the male chickens need to remain in the same environment to keep their “femaleness”. The principle of their technology, however, is the same as the approach I’m proposing: by selectively suppressing the expression of the gene DMRT1 in gonadal tissue,  it will result in male-to-female sex reversal and ovary formation. I, however, want to target the regulatory sequence(s) that controls DMRT1 expression in gonadal tissue.


It should be noted though that this technology (SOOS) only has a 60% success rate. In other words, 60% of the batches they test are female but this includes ZW females as well. So they don’t have a very good success rate at the moment.


3. Creating hens which only lay female eggs/the male embryo never develops https://www.i24news.tv/en/news/israel/technology-science/1643625207-israeli-firm-develops-hens-which-only-lay-female-eggs

The technology is trying to create a genetic trait that is passed down only to males. This mysterious trait is sensitive to blue light, such that when embryos with this trait are exposed to blue light, it causes development to stop. I couldn’t find much more information on the trait or how early development stops. 


This technology is trying to prevent male chicks from developing as early as possible whereas the approach I am proposing will allow those males to be hatched and used for egg-laying. 


4. Raise the male chicks as meat chickens

There are some countries in Europe that are proposing to do this. Known as “dual purpose” chickens, the male chickens (of egg-laying breeds) are reared to be used for meat consumption. For many hatcheries, this isn’t a financially viable option though. 


5. Develop plant-based/Cultured/fermented eggs

Plant-based eggs are another alternative. Currently though, production costs are still very expensive (plant based eggs are more expensive than free-range, organic eggs). Additionally, they’re not as nutritious as chicken eggs and on average contain less protein than chicken eggs. Plant-based eggs also contain lots of preservatives and additives. Therefore, I think plant-based eggs have potential, however, they’re not a sustainable alternative to chicken eggs.


In summary, the approach I’m proposing will enable the male chicks to be hatched and used as egg-layers. No culling, no expensive sorting machinery but twice as many eggs may be produced with the same resource input.