# If I set eggs this morning at 8am-is today day 1 or is tomorrow day 1?

Discussion in 'Incubating & Hatching Eggs' started by Kelly G, Oct 26, 2010.

1. ### Kelly GIt's like herding cats!

Just wondering how to determine what "day 1" is...is it the day you set the eggs, or the next day?

I may be over-thinking this, but I work in the medical field; infertility, to be exact. Calculation "day one" is very important for gathering information and calculation timing for procedures. "Day one" for us is the first day of "full flow" (sorry to be clinical). And when that starts is how we determine "day one."

Is there a better or worse time for starting eggs?

2. ### CindiloohooQuiet as a Church Mouse

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Dec 19, 2009
Southwest TN
Generally my rule is if they are set in the a.m. the day they are set is day 1. If they are set in p.m. then the next day is considered day 1.

3. ### rebel yellSongster

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Jun 27, 2010
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8am tomarow will be day 1.

4. ### LaurenM23Songster

Jun 16, 2010
King George, VA
I just think of it as: the point as which the eggs have been in the bator 24 hours...or 1 day. If you set them at 8 AM this morning, then at 8 AM tomorrow they will be at Day 1. Happy hatching!!!

5. ### harris farmChirping

Aug 8, 2010
Louisiana
Quote:Im with u after 24 hrs is the first day

6. ### RidgerunnerFree Ranging

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Feb 2, 2009
Southeast Louisiana
You might read my post in this thread. I think it will explain it. Other than Cindiloohoo, the others are right.

https://www.backyardchickens.com/forum/viewtopic.php?id=319371

In calculating hatch day for chicken eggs, the day of the week you set them is the day of the week they should hatch. If you set them on Tuesday, they should hatch on a Tuesday.

7. ### RathboneSongster

Oct 25, 2010
Mojave Desert
I am setting eggs under a hen when they go broody. Three hatches later - all three clutches hatched at day 19. I have silkies so don't know if that makes a difference?

8. ### shelleyd2008the bird is the word

Sep 14, 2008
Timing starts the moment you set them in the incubator. If you set them at 8 am on the 1st, they should start hatching at 8 am on the 21st. If you set them at 8 pm on the 1st, they should start hatching at 8 pm on the 21st. Some people count set day as 'day 1' if they were set in the morning and the following day as 'day 1' if set in the evening. That's too confusing for me

9. ### RidgerunnerFree Ranging

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Feb 2, 2009
Southeast Louisiana
As you can see, there is some disagreement on how to count. The real problem is when to start. Timing does start when they go into the incubator. No question about that. I personally don't like counting day 1, day 8, day 18 and such. I think the terminology should be days of development instead of day this or that to help get rid of the confusion. The way I look at it, an egg does not have 24 hours worth of development one second after it is put in the incubator. It has to develop 24 hours before it has 24 hours worth of development. If you are going to candle the eggs, you should look at the pictures for how many days it has developed to see what the pictures should look like. For example, if you are going to use the pictures for 8 days of development, you should candle the eggs after 8 full days of development, not 7 days and 1 second. Lockdown should be after 18 days of development, not 17 days and 1 second. So a chicken egg that is put in the incubator at 8:00 a.m. on the 1st has one day of development at 8:00 a.m. on the second. 18 full days of development will have passed at 8:00 a.m. on the 19th. Hatch should be at 8:00 a.m. on the 22nd. It will almost never be exact, but that is the time you should shoot for. I also do not think the exact timing of lockdown is that critical. The two things you do at lockdown is up the humidity and stop the turning. I think the two are related in that they are both directed at stopping the chick from sticking to the shell or membrane, so as long as you do them both together, it doesn't matter that much if you are several hours early or late. As a matter of good practice, I try to go into lockdown pretty close to 18 days of development but I'm not sure it is that critical to hit it exactly.

Hatching is not an instantaneous process. The chick pips, then rests, sometimes for many hours. Then it zips. Usually it pops out of the shell pretty soon after completing the zip, but sometimes it rests a bit first. They do not all hatch at exactly the same time either. Some eggs hatch earlier or later than others, even if the conditions have been about the same during incubation.

Some of the things that I know of that may affect when an egg will hatch. If the incubation temperature is a little high, the hatch will be early. I've had them hatch two days early in an incubator because of this. If the incubation temperature is a little low, they will hatch late.

How you store the eggs before incubation can have an effect. If the storage temperature is high, the eggs can partially develop and they can hatch earlier than expected.

The size of the egg makes a difference. I've read that smaller eggs will hatch earlier than larger eggs. I don't know if this means that eggs from breeds that lay smaller eggs will hatch faster than eggs from breeds that lay larger eggs or if they mean that the smaller eggs from the same breed will hatch faster than larger eggs from the same breed. They just say smaller and don't explain it.

I've seen a paper (I think from the University of Virginia but I have not been able to relocate it) that said some chickens are genetically programmed to hatch earlier or later than others.

My broody this past summer when it was in the upper 90's spent a lot of time off the nest hob-knobbing with her buddies, but on coooler days, she spent more time on the nest. I assume her instincts told her with those air temperatures she did not need to be on the nest as much.

Kelly G, I don't think I have addressed you question exactly. I am not aware of any better or worse time to start the eggs. I've had about the same hatch rates whether I start them in the morning or the evening.

10. ### Kelly GIt's like herding cats!

WOW! Thanks for all the GREAT information, you guys! I really, really appreciate it.

I can see that it's all about as clear as our instructions for our fertility patients...and I understand why they are so often confused! LOL

This is a GREAT resource...and I will also use it to schedule my "lockdown".

Big hug to all of you!!!