I have noticed with my hens that there cere changes in darkness or pinkness in the nostril bits.

Is this normal? Happened to my Hen before she laid, another when the weather got warmer.

 

What does it mean?

It is very normal for a hen's cere to change from a light tan to a crusty brown back to a whitish pink it varies. When it is darker brown it is when the hen is in what is known as breeding condition.