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How to tell if an egg is bad.

Discussion in 'Incubating & Hatching Eggs' started by GardenDave, Aug 10, 2013.

  1. GardenDave

    GardenDave Out Of The Brooder

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    Aug 5, 2013
    Hi all, Dave here.

    I am hatching eggs in an incubator for the first time and would like to candle them to see what is going on, but I'm not entirely sure what I should be looking for. I am a little nervous after earlier reading a comment suggestion that bad eggs could explode. I think I'll be wearing goggles whilst turning the eggs later [​IMG]

    So what do I look for? What suggests a good egg and what suggests a bad egg? What stages in incubation are best for candling and is there any time when it would damage the development of the chick?
     
  2. sumi

    sumi Égalité Staff Member

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    There are some great candling pics for reference here:

    https://www.backyardchickens.com/t/...g-candling-pics-progression-though-incubation

    and more pics, videos and discussions here:

    https://www.backyardchickens.com/t/750122/share-your-candling-pics-and-videos

    I usually wait until day 7 before I candle. You won't be able to see very much before then unless you have a strong light and a pale shelled egg. Second candle for me is at day 10 when I double check and toss any clears and eggs that doesn't look like they should and final candle is at day 18 just before lockdown to make sure everything's fine.

    Good luck with your hatch!
     
  3. BantamLover21

    BantamLover21 Overrun With Chickens

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    I usually candle my eggs at 7 days, at 14 days, and then at 18 days.

    A fertile, developing egg at 7 days will appear as a reddish/black blob with blood vessels extending out in a circular manner. Sometimes, you can see movement. An infertile egg will show no blood vessels, and a fertile egg that died will have a thin line of blood extending around part of the egg (this is called a "blood ring").

    At 14 days, an alive, developing egg will appear as a blob that covers half or more of the egg's inside. There will often be blood vessels extending upward towards the air cell, and you will often see movement. A dead egg of this age will appear as a motionless blackish blob, with no blood vessels up near the air cell.

    At 18 days, an alive egg will be almost completely filled up, with the only clear spot being the air cell. You will almost definitely see movement, and there may still be a few blood vessels visible.

    Sometimes, I also candle on day 20, just to reassure myself that the eggs are still alive. However, that is not generally recommended, as the embryo is getting into the hatching position, and shouldn't be disturbed.

    If for some reason some eggs haven't hatched by day 22-23 of incubation, I would also candle then in able to tell if the unhatched eggs were still viable. Good luck with your hatch!
     
  4. GardenDave

    GardenDave Out Of The Brooder

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    Thanks for the help folks. I don't have a candler at the moment so I've been using a torch, and I can't get anywhere perfectly dark so I have to just close the curtains and find a dark corner lol. It is hard to tell, although the pictures on the other thread help. Some of them look like they are totally dark apart from at one end it looks like there is nothing there, but then when I turn the egg I can see that the chick is obviously on one side as the other side is lighter. However I can not tell if they are alive or not.

    Some look a little spotty but I'm not sure if that is because the egg is not perfectly clean or not. I think I'm going to have to get a candler from somewhere - either that or get a better torch perhaps lol
     
  5. BantamLover21

    BantamLover21 Overrun With Chickens

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    Spotty eggs are typically eggs that are extremely porous. I've never had much luck incubating those, but some chickens consistently lay eggs like that.
     
  6. GardenDave

    GardenDave Out Of The Brooder

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    Unfortunately I experienced those 'exploding eggs' although thankfully didn't need goggles lol. There has been a bad smell for a few days coming from the room the incubators are in and from one incubator in general. I figured the smell was just the stuff on certain eggs because I'd read not to clean hatching eggs. They were in quite a state so I just went over them with a dry towel to remove the large and loose bits. As I went in yesterday evening to turn them I noticed one had developed a crack almost all the way around and the smell had worsened. It is nowhere near hatching time so I removed the egg only to find another in the same condition. So I'm down a few eggs now but still have plenty hopefully. Ironically the ones I lost were the ones I was hatching to make up for any loss through death or cockerel. The eggs that were bad were the spotty ones which BantamLover21 states not to have had much luck with. Looks like I'm joining that group lol.

    All the other eggs appear to be doing fine. I have some Polish, Silkies, Wyandottes, Leghorns, two lots of mixed but I can't remember exactly what the mixes are lol, and I just put in another lot of Wyandotte eggs which I will have on the allotment I think. (Don't worry, they are in an incubator of their own lol.
     

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