BCM hatching fail

[TexasBlues]

I do have a scale to weigh them. Is there a specific formula for weight loss % at different stages?
I’m collecting eggs this week and should have them incubating by the weekend. I’m leaning towards filling up the incubator with 40. But maybe my chicken math is out of control.

 

[wrathsfarm]

I do have a scale to weigh them. Is there a specific formula for weight loss % at different stages?
I’m collecting eggs this week and should have them incubating by the weekend. I’m leaning towards filling up the incubator with 40. But maybe my chicken math is out of control.

https://avianaquamiser.com/posts/how_to_weigh_eggs_and_calculate_weight_loss/

 

[wrathsfarm]

I do have a scale to weigh them. Is there a specific formula for weight loss % at different stages?
I’m collecting eggs this week and should have them incubating by the weekend. I’m leaning towards filling up the incubator with 40. But maybe my chicken math is out of control.

I found this also..

https://www.backyardchickens.com/th...-incubate-chicken-eggs.1613189/#post-27553285


Read post #8

 

[karint]

I like being closer to mid 20 -30% with my Marans eggs. My last hatch in September went well with that.
Do you have a scale you can weigh the eggs to follow weight loss? Then you could adjust accordingly as you go.

I just started weighing my eggs. The internet says loose 11-12% by day 18. Is that what you shoot for?

 

[FunClucks]

I just started weighing my eggs. The internet says loose 11-12% by day 18. Is that what you shoot for?

Yes. I shoot for 12% weight loss and measure initial weight before I put them in the incubator, then calculate final target weights for each egg in Excel. I figure out what amount of weight the egg should lose each day to obtain the target weight loss by day 18. Then I multiply the daily target weight loss by the number of days since I set them. So if I"m measuring weight on day 6, I take the initial egg weight and figure out what that egg should weigh on day six, and then compare to actual egg weight on day six. If the actual weight is higher than expected I might decrease humidity to increase weight loss. If weight is lower than expected, I might increase the humidity slightly, but this rarely happens in my setup. Then give it a few days to a week and measure again and compare to targets.

In order to get good hatching results, all the eggs you set should be as close as possible to the same size, and have the same shell permeability. You can only set your humidity at one value, which may not be optimal if you have a wide range of egg sizes and/or shell permeability. So large eggs and small eggs should be hatched separately (due to size and how much moisture has to evaporate for air cells to be the correct size at hatch), and Marans eggs and other eggs may need to be hatched separately due to differences in shell permeability.

 

[karint]

Yes. I shoot for 12% weight loss and measure initial weight before I put them in the incubator, then calculate final target weights for each egg in Excel. I figure out what amount of weight the egg should lose each day to obtain the target weight loss by day 18. Then I multiply the daily target weight loss by the number of days since I set them. So if I"m measuring weight on day 6, I take the initial egg weight and figure out what that egg should weigh on day six, and then compare to actual egg weight on day six. If the actual weight is higher than expected I might decrease humidity to increase weight loss. If weight is lower than expected, I might increase the humidity slightly, but this rarely happens in my setup. Then give it a few days to a week and measure again and compare to targets.

In order to get good hatching results, all the eggs you set should be as close as possible to the same size, and have the same shell permeability. You can only set your humidity at one value, which may not be optimal if you have a wide range of egg sizes and/or shell permeability. So large eggs and small eggs should be hatched separately (due to size and how much moisture has to evaporate for air cells to be the correct size at hatch), and Marans eggs and other eggs may need to be hatched separately due to differences in shell permeability.

Thanks. That’s really helpful. My next batch is only going to have maran so that will make it way easier to monitor. My current batch has multiple breeds and it is almost at lockdown so probably to late for that one but moving forward I feel like I have a better idea of what to do to try to be more successful.

 

[TexasBlues]

Thanks for the links. This seems to be working out.

(Starting weight of egg) = 53.2grams
The next step is to figure out how much I want the eggs to weigh at the end of the incubation period. We’re aiming for a 13% weight loss, so:

(Goal weight at end of incubation) = (First day weight of eggs) X 0.87

For our eggs, that is:

(Goal weight at end of incubation) = 53.2 X 0.87
(Goal weight at end of incubation) = 46.28

It’s also useful to know what our daily weight loss goal is:

(Daily goal weight loss) =
(First day weight of eggs) – (Goal weight at end of incubation)
21


(Daily goal weight loss) =
53.2- 46.28
21

(Daily goal weight loss) = 0.329g​

Eggs are at day 9. Current weight of 50.0grams
9 x 0.329=2.96
53.2-2.96=50.24. So they have lost 1/4 gram more than anticipated. Maybe I should up the humidity?

https://avianaquamiser.com/posts/how_to_weigh_eggs_and_calculate_weight_loss/

 

[FunClucks]

Thanks for the links. This seems to be working out.

(Starting weight of egg) = 53.2grams
The next step is to figure out how much I want the eggs to weigh at the end of the incubation period. We’re aiming for a 13% weight loss, so:

(Goal weight at end of incubation) = (First day weight of eggs) X 0.87

For our eggs, that is:

(Goal weight at end of incubation) = 53.2 X 0.87
(Goal weight at end of incubation) = 46.28

It’s also useful to know what our daily weight loss goal is:

(Daily goal weight loss) =
(First day weight of eggs) – (Goal weight at end of incubation)
21


(Daily goal weight loss) =
53.2- 46.28
21

(Daily goal weight loss) = 0.329g​

Eggs are at day 9. Current weight of 50.0grams
9 x 0.329=2.96
53.2-2.96=50.24. So they have lost 1/4 gram more than anticipated. Maybe I should up the humidity?

Your numbers look good. How are they doing now?

 

[TexasBlues]

I just weighed that same egg at day 16. It should be around 47.9g and actual weight is 48.3g. This is the equation for targeting a 13% loss. Maybe I’m closer to the 12%.
My incubator goes from about 35% humidity and drops to 20% before I add water.

 

[TexasBlues]

I would suggest running a lower humidity for darker Marans eggs. I ran 20-30% essentially a dry hatch the first 18 and not over 50 for lockdown on my last hatch. 99.5 for temp.
Breeders that I've learned from say because of the harder shells and darker pigment, Marans eggs retain more moisture not needing the higher humidity during incubation.

If this was your issue I can't say for sure.


Were they your eggs or shipped?

Hope your next hatch is much better.

You think 50% is a good humidity at lockdown? Mine go on lockdown this evening. Right now we are around 30% on day 17.