What symptoms did they have? Sneezing, bubbles in eyes, swollen eyes, nasal drainage? Many chickens in the US are not laying now because of the decreased amount of light. Yours may start up as the daylight hours get lighter soon. I usually see an increase in laying between now and Feb. Many diseases can cause a temporary decrease in laying, but they may lay better later. I would not cull my flock if they had infectious bronchitis or even MG, but I would for more serious diseases, such as ILT or coryza. Can you add your location to your profile page?Very informative...and depressing. I have no way to know what type of illness my birds had this summer. It appears I need to cull my entire little flock of 9 and start over. They had the resp. Before they were of laying age and only 2 are laying. So their reproductive systems apparently have been damaged.