Weight loss during incubation.

[steffanos]

Hi,
I am currently monitoring total weight loss for a batch of chicken eggs in an incubator (in this instance 13% over 18 days), it is now day 8 and the the weight loss is on target.
My question is how do I modify the equation having removed a number of eggs that proved infertile on candling? In other words, do I :

1. Weigh the eggs on removal and assume that they have lost the same weight pro-rata as the fertile ones.

2. Weigh the eggs and assume no weight loss due to infertility.

3. Should all the eggs be weighed and marked individually before hand, as opposed to in total, which is how I have done it.

TIA.

 

[Davidd]

Hello, i would weigh individually-but having said that it is not critical a few percent either way will not do any harm to chicken eggs- only really rare, hard to hatch in incubators- and normally parrot like birds need strict humidity recording.Humidity should be based over the whole incubation period and as i said an average loss over 21 days will be fine.
regards, Davidd

 

[chrismahon]

I assume they are all the same breed. Remove the infertiles and weigh the remaning fraction of the original batch. So say you started with 24. Your first weight was 24/24ths and it reduced. Say you now have 16 eggs left. Take their weight x 24/16 = the weight of the original batch if there were no infertiles. Recalculate your % loss. I realise that all the eggs were not the same weight when you started and Davidd is correct to weigh each egg. But it will be close enough and you won't need to buy super accurate fine scales.

If the eggs are different breeds of different sizes I don't know what to suggest? You don't want to leave infertiles around going off.

 

[steffanos]

That's exactly the point they are all different breeds, and vary a lot.
Chrishmahon, thanks for your answer, but you miss the point of the question I think. I am not asking about the simple maths of the ammended equation.
It would be correct to do what you say if the unfertile ones had lost the exact same %age as the others, perhaps they do? But if they haven't your new calculation would be out by 16(remaining eggs) / 8 x weight not lost by infertile eggs/, thereby rendering the new calculation quite a way out.
And with the eggs being differing sizes, for example 6 aracauna eggs (online order) heaviest 51grm, lightest 34grms....but I stuck them in anyway!!
So really all I'm asking please is: Do infertile eggs lose the same %age weight in an incubator as fertile ones?
Thanks again.

 

[Tim]

Yes, weight loss comes down to evaporation of water from the egg which varies according to the porosity of the shell. This varies between species and breeds and even from egg to egg slightly but the infertile eggs are still losing moisture.

I've had this problem in the past. It's evident to see if you set a batch of eggs and weigh every one - they all lose moisture at slightly different rates.

As said earlier, with chickens, it's not so critical but if you incubate Wildfowl or something more exotic, then you need to be thinking on an egg by egg basis. The way this is done is by running 2 incubators and 1 hatcher: The hatcher is set to high humidity and where the eggs end up 3 days before hatch but the incubators are set slightly high and slightly low in humidity, then eggs can be moved between the two to compensate for the porosity of the egg shell.

The weights are graphed and you can see whether the egg needs to be moved to a higher humidity / lower weight loss incubator or lower humidity / higher weight loss incubator...

As long as the total weight loss is right before hatch, you can correct.

I wrote an article on this when I first started the site here: Weight Loss for Incubation

It's a little out of date now but is still pretty acurate. As I say, a little extreme for chicken eggs which are generally acepted as being one of the easier species to hatch.



The main

 

[steffanos]

Thanks for that Tim, exactly the info I was hoping for. I've set a graph in Excel and on day eight it hit the line exactly. Now with the infertile eggs removed, I will be able to ammend the calculation accordingly.
Likewise to you too Chrismahon - you're equation will put me on track.
Thanks to everyone for taking the time to answer.