Please beekissed, will you tell us more about your rigorous cull schedule you mentioned? TIA
I just cull for several things at least once a year, after doing the "finger test" for current egg laying. This is done when egg laying should be at it's peak...I keep calendars with each daily egg count carefully marked so I could divine the rhythm of my flock until I pretty much learn it and don't record so much anymore. Every flock is different, depending on their age, abilities, environment, health.
Then I cull for laying, general health appearance, usefulness to the flock(is she older and a sporadic egg layer but still a great broody and mother? If so, I'll support her for a season or so) and feed thriftiness. Birds that are first to the trough and last to the nest are an easy target when it comes to culling time. Career broodies....birds that start out young at going broody and go broody more than 2 times a year~I don't need 'em. One or two good broodies are enough for a flock the size of mine...and only if they limit their broodiness.
I had one White Rock that seemed to go broody JUST when I needed her to do so each and every year. She is still in my original flock...not to mention, when she isn't brooding, she lays every day. She is 5 going on 6 years old.
Then, sometimes, if the hens change during the year and I notice changes that I don't keep in my flock are happening....extensive periods of nonlaying, ratty appearance, etc. Even if this occurs in non-peak months of lay, I'll sometimes do a second culling of the hens. This happens rarely in my flocks...but it does happen. I don't want to support a hen all year long to get her up to my regularly scheduled cull session...can't afford to feed anyone who doesn't work or stay top notch on my regimen.
Sometimes if you see changes in appearance in a formerly good and healthy, but aging, hen this could mean she will start developing reproductive problems or other health problems associated with age. Best just to cull her because age doesn't go away.....much to my own dismay.
I left one very old White Leghorn in my flock past the time I should have because she was still laying sporadically and her eggs were huge and mostly double yolkers. She was sort of a favorite of mine, so I skipped her in several cullings. But her laying pattern and the double yolk eggs should have been a warning signal to me that, coupled with her age, she was starting to have reproductive changes.
She was still very healthy in appearance and very active, but when I opened her up she had a huge growth inside of her that was just layers upon layers of cheesy, egg yolk-like material. It filled the whole palm of my hand...which is pretty big for a small Leghorn to be carrying. Probably really inhibited her organ function and was more than likely uncomfortable...but I let my sentiment overrule my good judgement and I ignored the signs of impending health problems.
I can't be assured that she suffered but any bird that size having a growth of that magnitude would have to have had some discomfort....lesson learned. I won't have an animal suffering under my care.
