[Bodger]

The breeder discounting the possibility of Mareks due to her comb being to bright is incorrect.
In my experience Mareks will suddenly start to show itself in the healthiest and best of your chickens if they have the virus. On a number of occasions, I've had chickens ready for shows in the peak of condition, only to go to the pens literaly to see them come down with it overnight.

A bird can have Mareks without showing any symptoms what so ever for a long time and suddenly Bingo ! They have it. Stress will quite often bring it on and this is why its quite common for  the onset of laying in young pullets to show  cases in your flock.

[muntjac]

here here , both bodger n sally