What does this bump on the head mean?

Photo: Marcel Berendsen

Ask yourself the following questions:  What do I see?   What does it mean?   What should I do?

This is Practical guide to improving egg quality

• LOOK: This egg has a clear bump on its ‘head’.

• THINK: It might be a signal of a Newcastle disease (ND) infection. ND causes misshaped eggs.

• ACT: It is good practice to vaccinate against this disease.