CANDLING EGGS
I don't have a BW laser torch for candling
eggs. The cost of purchasing one here in Australia would be astronomical with
the exchange rate almost tripling anything we buy from the U.K. I use a much
cheaper one here and it does the job adequately but you need to replace the
batteries when they are about half spent or you don't have the strength in the
light. I start to candle the eggs when the second egg is laid. On the rarest
of occasions, I have seen fertility in an egg on the day after laying but this
is extremely rare. The first sign of fertility is a slight orange glow to the
yolk which is because the blood vessels are beginning to form. Next, a small
circle of blood will appear in the centre of the yolk about 3mm in diameter,
followed by a larger circle around it of about 6mm diameter. At this point you
should be able to see the heart. Take a close look! You will see a blob of blood
and see it contracting as it beats. Take a deep breath here and say to yourself
"This is life in the making and I am part of it" (makes you feel good) This
is where most people would begin candling at day four or, when the third egg
appears, and they would see all of this at once. Unfortunately, much can happen
between conception and even this early stage which I will come back to later.
Each day from now on you should see an intricate web of veins forming over the interior of the egg surface. By checking each egg every day you will soon get to know which is egg one, egg two etc and; you will be able to detect if there is a clear egg in the sequence as it will not colour up on time. This continues with more and more veins appearing and the egg darkening up until about day 16 when the egg will appear as a solid mass. Allowing for the fact that not all eggs will hatch on exactly day 18, the chick will usually break through the inner membrane on day 16 or 17. When you candle the egg now it will look somewhat like an addled egg, being rather uneven inside and with a large air pocket. This is because the chick has broken the inner membrane. Put the torch to the air pocket and wait to see the chick moving. It should hatch sometime within the next 24 hours depending on exactly how far the chick has progressed. The appearance of the egg shell will remain the same until pipping has commenced then the egg will appear to be mottled.
Examples - you check the egg and see the chick has broken through the membrane last thing at night but there is no pipping evident. Next morning it has hatched. Another egg checked at the same time may be several hours further along and the chick has loosened itself from the inner membrane of the egg and begun to turn in the egg pipping around the shell. Next morning it too has hatched but this may have taken place minutes after your evening inspection whereas the first chick did not hatch until 5 a.m. I have literally checked eggs and said to myself "This will be hatched by tomorrow" and gone back to the same box to ring another chick and seen the other one emerging from the egg.
PROBLEMS AND TIPS
For those who do not have a torch (of any kind) I strongly recommend that you purchase one. When I consider my early days when all I could see was a clear egg from the outside and blamed it all on infertility and had no idea how to remedy the situation, I shudder to think whether I would have continued breeding birds if I had not found better ways of doing things and, in my opinion, this is definitely a must.
PROBLEMS
Clear eggs - that is eggs which actually have never been fertilised - tend to have a larger air pocket. You will find that by the time you have three or four eggs, the air pockets of all the early eggs have increased through the exchange of gases but, the in the clear egg, the yolk will begin to harden and you can, with careful observation, detect this. It will be more obvious in some cases.
Addled eggs - that is eggs in which the embryo dies at any point prior to an attempt by the chick to hatch-eggs which take on the initial orange glow but seem to become blurry inside instead of colouring up are addled. Eggs which begin to colour up and then a thick red streak appears are addled. These eggs will often continue to show as being "good" for quite some time but I have never seen one go full term. Eggs which seem to go foggy inside as incubation progresses are "becoming addled" Often this can be the hen (usually about midway through the term) or older chicks in the nest rolling about . I have successfully transferred these eggs to other nests and saved them.
Dead in Shell - the two reasons for dead in shell are weak embryos due to disease, genetic weakness or dietary deficiency. Dead in shell is where a chick has begun to pip but has been unable to get out of the shell. I have not known humidity to be a vital factor, however, some chicks can get stuck to the membrane if they take too long to hatch and the membrane dries out.
TIPS
Clear eggs - Check your pairs for compatibility. I have had birds paired and the hen has laid only to discover they were never bonded. If you don't see favourable interaction between your birds then chase them onto the same perch and see what behaviour they exhibit. Get someone to show you AI. Even if you don't use it you should be able to identify a cock in condition. Many of my original pairs this year didn't fire and I had to identify where the problems were and remedy them. Cocks which weren't ready to fill in July are filling in October.
Ensure you prepare your birds for breeding. Plenty of fresh foods, vitamins and protein leading up to the breeding season.
Check the eggs with your torch. Some eggs are laid with tiny air bubbles and are useless. Check the quality of the egg shell. Does it look normal, calcified, porous etc?
Addled eggs - I have one cock bird who fills every egg and then goes in the box and addles the eggs. I am lucky to get one chick even if I remove the eggs as soon as they are laid. Eggs which seem to be addled after a few days need to be examined with your torch. Check for rotating yolks! Hold the egg horizontally with the yolk at the top and turn the egg. Does the yolk stay where it is or stay at the top. It shouldn't move. The yolk is held by small strings which suspend it and the yolk will only move if these are broken. Eggs like this can go on to produce healthy chicks provided the hen is gentle with them. After the web of veins has engulfed the egg, it holds the embryo in place, however, too much movement prior to this will see the egg become addled. Eggs which seem to be colouring on one side only, likewise, can usually go full term unless they are handled roughly .
Dead in shell - Only you can answer this one! Widespread dead in shell will be due to disease, most likely Chlamydia or Polyomavirus. Dead in shell in one nest will be due to a problem in that pair, either due to genetic incompatibility or nutritional deficiency. Try increasing the protein and vitamin level. If the same results, split the pair.
Chicks which haven't hatched in 24hours are checked with the torch again. If pipping hasn't commenced then they are best left alone. If pipping has commenced and there is plenty of movement all should be O.K. If there is little movement I try to help. This is difficult. Chicks who have exposed themselves to the outside air can get stuck as the membrane dries and they can't turn in the egg to finish pipping. On the other hand if you help a chick too early you can kill it. I usually get a pin and pick around the egg at the air pocket and half crack it open. If there is no sign of blood it is safe to open the egg. Any blood and the chick is placed under the hen to hatch by itself. It is rare that I attempt this and success is usually only around 50%.