[Stereo]

We've hatched lots before but Mrs Stereo has always dealt with all the candling etc. I set 23 eggs a week ago and have just candled them. They are copper marans and araucanas. On most of the eggs I'm just getting a dark blob in the middle of the end with light at the ends. We candled some sussex eggs the other day at about 5 days to check fertility before selling them and you could see all the veins and stuff. Obviously easy eggs to candle.

Question is, can I take it that a think mass in the centre means the egg is fertile? Or could it be something else? Would an infertile egg allow the egg through after being lightly cooked for a week or could the mass be the yoke rotting or something?

Anyone got any good image resources?

[chrismahon]

Dark eggs are always a problem Stereo. If you have nothing to see they are infertile and rotting. The dark blob should be the embryo. You can get embryos that have died at about 3 days, but compare the size to the others.

[HesterF]

Yep, I had the same problem with Marans last year. Duck eggs are brilliant - you can see everything. Dark blob is probably a good thing but might be a yolk. The eggs won't go bad if they're infertile (well not in that time anyway) - it's worse when they die partway through, that's when they become explosive - so no rotting yolks.

H

[Steph Hen]

My family hatched chicks when I was growing up, and never had much success with candling, lots of grey blobs and blurs. I now know that the room was either too bright or torch not strong enough as what I see is typically- nothing but the darkish shadow blob of yolk in an infertile or black dot with veins of developing chick. If I'm not sure i draw in pencil what I see and come back to it a few days later. Marans are hard to see though, but Araucanas were the easiest, I could clearly see all the veins and the embryo moving about later on.

[doganjo]

Weighing before and after is a good indication of whether they are fertile or not.  Haven't done it before but I will next time.  Not sure if you can do it half way through but worth a try
Eggs should lose 11-13 per cent of initial weight during the first 18 days of incubation, and shows that the  egg is fertile - it won't lose water through evaporation otherwise.

[HesterF]

I've been weighing the eggs this time around - trying to prevent my hatching problems of last year. It's worked so far with 100% hatch  from my first batch of chicken eggs (which at half way through had lost way too much weight whilst the duck eggs hadn't lost enough). BUT there wasn't much difference in weight between the fertile and infertile duck eggs after a week - which was when I ditched the infertile ones. I know fertile eggs generate more heat so they should lose more water but as I say, I wouldn't have said it was a dramatic difference.

I think generally the weight loss is more that you should aim for them to lose 13% overall so you adjust your incubating conditions accordingly rather than assuming they will lose 13% and judging fertility by that.

[Clansman]

It'll only rot if the embryo starts developing and then dies or if the egg has a crack/chip that allowed bacteria in, they won't cook

We've just finished eating a load of clear duck eggs that had been in the incubator 2 weeks 

[HesterF]

That's really interesting that you have eaten them. I must admit I've always binned them but it felt awful last year binning goose egg after goose egg thinking they would probably be fine to eat.

[Clansman]

When I worked in commercial hatcheries 20 years ago or so, they used to sell all the clears to bakeries but I don't think they are allowed to do it nowadays.

[Stereo]

Thanks for all the comments. We candled them and pretty sure we've got 100% with one suspect.

[waddy]

I bought a Brinsea ovascope for candling but found it hard to see in most of my (coloured) eggs. No where near as good as a really bright torch. Our first eggs (and hopefully first ever hens) are due to come out from Wednesday. I have just stopped the cradle turning and am about to bump the humidity up, but I am concerned that some of the eggs (larger ones) haven't lost enough weight (around 9.5 - 10.5%). A few have lost more than recommended so I have had a dilemma. They all seem to have a decent air gap so I will keep fingers crossed and be ready to help if necessary.


Helen

[HesterF]

Helen, I've got the same problem with my duck eggs due on Saturday(ish). The Cayugas have all lost more than they should have done by the end, the Silver Appleyards have all lost less than they should have done. Complete dilemma. The following batch are all Silver Appleyards and are all on target. Trouble is then you need a lot of incubators.

[Steph Hen]

When I worked in commercial hatcheries 20 years ago or so, they used to sell all the clears to bakeries but I don't think they are allowed to do it nowadays.

Omg!
I was discussing just yesterday that I eat eggs that had been under a broody for a day or two but would never sell them! Anything longer than couple of days and they're dog food.
I also keep back and eat any eggs that have slipped through the net and are a couple of weeks old rather than sell them. Seems eggs really are very stable, if they can cope with 37.5' for a fortnight and still be safe for baking! Thanks.
 

[hughesy]

I use my LED head torch for candling these days. The light intensity is adjustable and the end of the egg fits nicely into the rim around the lens. It doesn't give off heat like a traditional bulb either.

[Stereo]

When I worked in commercial hatcheries 20 years ago or so, they used to sell all the clears to bakeries but I don't think they are allowed to do it nowadays.

Omg!
I was discussing just yesterday that I eat eggs that had been under a broody for a day or two but would never sell them! Anything longer than couple of days and they're dog food.
I also keep back and eat any eggs that have slipped through the net and are a couple of weeks old rather than sell them. Seems eggs really are very stable, if they can cope with 37.5' for a fortnight and still be safe for baking! Thanks.

I believe most shop eggs are already a week old when they hit the shelves and they put another 3 weeks on that. We put a best by date of 3 weeks from laying to be safe but few get that old. If they do we just do extra baking.