How to count the hatching days

Discussion in 'Incubating & Hatching Eggs' started by waldeneffect, Mar 3, 2012.

  1. waldeneffect

    waldeneffect Out Of The Brooder

    Oct 7, 2008
    southwest Virginia
    This feels like a stupid question, but I'm a bit stumped on when exactly day 21 is. This is my fifth hatch, and they all seem to be coming out on day 22 each time...or at least what I think is day 22. That might mean I need to increase the temperature in my incubator, but it also might mean I don't know how to count.

    So, my question is --- if you put chicks in an incubator in the morning on a Friday, is day 21 three weeks from that Thursday or three weeks from that Friday?

    Do you have to factor in the time it takes for the eggs to come up to the temperature inside the incubator?

    Does anyone know if the incubation time for chickens is really 21.5 days, or 20.5 days, or 21 days? For example, if I started those eggs in the morning, should I expect to see chicks hatching in the morning three weeks later, or in the evening? (I like watching them come out, so it would be handy to know what time of day to put them in to make that happen.)

    Thanks for your help!
  2. dbcooper02

    dbcooper02 Chillin' With My Peeps

    Apr 20, 2007
    SW Washington
    Eggs set on a Friday morning are expected to hatch on the third Friday morning following. Of course this doesn't mean that all the eggs will zip at the same instant. Its just a rule of thumb. I don't think its necessary to make any allowance for the eggs to come up to temperature. If you find you are consistently hatching on day 22 you might want to up your temp just a bit.
  3. waldeneffect

    waldeneffect Out Of The Brooder

    Oct 7, 2008
    southwest Virginia
    Yep, I was counting the third Friday morning as day 22. If you count the days, that means the day you put chicks in the incubator is day 0, not day 1. Good to know! Now I know that my incubator is doing its job and the chicks are actually hatching on day 21. :)
  4. Canadianna

    Canadianna New Egg

    Jul 15, 2013
    Violet Hill, Ontario
    Okay, so I'm late to the game, but I'm having the same issue.

    My chicks hatched today: Day 23.

    My thermometer isn't digital, so it's not particularly specific, BUT how many degrees should I increase the temp to have it hatch on the proper day?

    Is there a formula? 0.5 degrees = 24 hours?

    Thanks in advance,

  5. chickenlindz

    chickenlindz Chillin' With My Peeps

    Oct 5, 2013
    I'd say if your getting good hatches with healthy chickens don't worry about the day. I'd rather stick w what works vs trying to change something to try and ensure a perfect 21 days.
    1 person likes this.
  6. sktlmt

    sktlmt Chillin' With My Peeps

    Dec 27, 2013
    I am so glad someone had asked this question. I took a clutch of abandoned eggs from a not so broody who hid the eggs. I put them in the incubator April 25 so hatch day should be May 16. 2 of them hatched on day 20 they are now in the brooder box. I treid to leave them but they were freaking out. Climbing all over the other eggs and I worried they would injure themselves.
  7. GuamChicken

    GuamChicken Out Of The Brooder

    May 14, 2014
    I have realised that they never hatch " on time " . It's just like humans, who delivers exactly on their due date ? My unscientific observation is that older eggs ie: 7-14 days, hatch at the 21 day mark. Newer aggs, like less than a week, seam to hatch a day early. But thats just an observation, the point is, its never exact. It sort of depends also how long it takes your eggs internal temperature to get up to where it starts to develop. We cant really measure that.
  8. wynn4578

    wynn4578 Chillin' With My Peeps

    Apr 6, 2015
    My eggs will usually begin hatching on day 20. I get a good hatch and my chicks are healthy so I don't bother adjusting. If my hatch rates were suffering or I was seeing chicks with issues in my case I would re-calibrate and possibly drop the temp a bit.
  9. GuamChicken

    GuamChicken Out Of The Brooder

    May 14, 2014
    Yes, I agree. It seams almost always the hatch starts on day 20. If I don't get a at least one pip at day 20 , I begin to get worried.
  10. RubyNala97

    RubyNala97 Overrun With Chickens

    Apr 9, 2015
    Hudson Valley, NY
    So, do you count day 1 as zero "0"??? I was kind of wondering this too because I printed off a sheet to keep track of your hatch, Each day you fill in the specifications of temp, humidity, hand turning, etc. And it counted day 1 as day 1. I actually set my eggs on Wednesday night before bed but didn't start counting until Thursday morning. So hatch day should have been the third Thursday after, but If you count day 1 as 1 (according to the hatch-track sheet), then 21 days falls on the Wednesday before, not Thursday. I was and still am confused about this.

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