Solving the mystery of blood spots on Maran eggs
PUBLISHED: 17:58 25 April 2014 | UPDATED: 21:05 29 April 2014
Q - I bought four Marans point of lay that have just started to lay. The eggs of certain birds have red blood spots all over them, and when you inspect the yolk it always has two white bits attached to the yolk, one on each side
I know the hens have never run with a cock bird, and so can’t work out why they look fertilised. The eggs are collected within minutes of laying and refrigerated so, even if by some miracle they were fertilised, it would be too cold for the embryo to develop. Could it be linked to the blood spots? It’s a real puzzler - any help would be welcomed as your advice has always helped in the past.
Andrew Williamson, via email
VR?writes: If the blood spots are on the outside of the shell, then there is a colony of red mite in the hen hut and you will need to treat for red mite.
If the shell has blood smears on it, this can happen when a pullet first starts to lay and is caused by the rupture of tiny blood vessels in the vent. I would not expect this as a regular occurrence in birds in full lay, however.
If the blood spots are in the white or around the yolk, then this is caused by leaky small blood vessels higher up the oviduct and is known as meat spots (commercially, hens are culled for this) or do not breed from the bird as this defect is inherited. It is not hurting the affected hens.
If the blood areas around the yolk are like small red strings radiating out from a centre, then the egg is (or was) fertile.
The white strings are called chalazae and help to keep the yolk stable and the potential embryo at the top when the egg is moved. They are most prominent in a really fresh egg, which is why you may not have noticed them in shop eggs. When judging eggs, this is one of the features we look for in assessing fresh egg contents. If eggs are being saved for incubation, and turned on a regular basis to prevent the membrane from sticking to the shell, care must be taken not to turn in the same direction every day as otherwise the chalazae get wound up and can catch around the embryo and throttle it. Breeders mark the sides of the eggs with, say, a cross and a zero, and turn to the right on one day and to the left on the next. Having eggs in an egg tray and lifting one side a couple of inches, then the other side the next, avoids having to handle the eggs – even clean hands will transfer some bacteria.