Red Blood in the egg yolk

Eggs with blood in them occur more often with brown hens than white ones. There are notable genetic differences among breeds. Broken blood vessels in the ovary or oviduct cause blood in eggs. If the problem occurred in the ovary, all the blood will be in the yolk. You see it in the egg white if it occurred at a later stage.

The following factors can cause burst blood vessels:

• Insufficient vitamins A and K in the feed – It is also very important that the vitamins are properly mixed through the feed
• An excessive amount of lucerne meal in the feed – It contains a substance that blocks vitamin A uptake
• Mould in the feed
• A continuous light program, or one with too many short periods of light and dark – Sufficient rest at night is important for hens
• Sudden occurrences of stress in the house – Panic movements can result in burst blood vessels.
• Avian Encephalomyelitis (AE or epidemic tremor) – Make sure you have an effective vaccination program

(Source:  Egg signals by Piet Simons)