I have done a ton of research on this topic since I lost a pullet to this disease. I just have some questions that I want to make sure I have clear in my head: Can this be transmitted (leading to fatality) to adult chickens, or are chicks and young birds most likely to be effected? I ask because the batch of chicks I hatched are the ones where the symptoms/death is coming from. All of my older birds seem fine even though they were obviously exposed/are now carriers. (I got rid of the breeding hens that produced the sick chicks) I am curious as to whether or not I should be worried about my 1+ year olds being exposed. Also, I am wondering if there is a period of time I need to keep any new chicks away from carriers. I read that after a hen's first molt, the likelihood of passing LL to chicks through egg is reduced by 95%. I plan on not breeding any pullets, but other than that, what is the first step in breeding for resistance? Thanks!