I don't know if any of this info will help, but here's everything that I did. So, back in 2021 my Barred Rock hens were a little over a year old. We had two hens die within a week of each other of Fatty Liver Hemorrhagic Syndrome (confirmed by state necropsy). Now, I'm convinced that my hens would've survived just fine, but the hemorrhaging was brought on by excessive heat. They were way too fat to cool themselves down!
First thing we did was to restrict all treats that weren't some form of veg. Now, we couldn't put the whole flock on a lower-feed diet because only 6 out of 14 chickens were candidates for losing weight. The other 7 hens and my Roo-Roo were either perfectly healthy or a little underweight. They couldn't afford a diet! So, what I did was monitor all of the hens' crops when they went up on the perch at night. Turns out, the fattest hens had crops that were so full some of them would be doing this swallowing motion, as if they couldn't keep it down
. The healthy or thinner hens had more conservative sized crops or less food overall.
So, the ultimate solution was to allow everyone food pretty much the whole day, but restrict right before they go to bed. Chickens naturally fill themselves up a ton right before bed because they'll be digesting all night. So, I got a little pen to put the fatter hens in when I decided they'd eaten enough (I would feel crops). Then, my healthy/skinny hens (some of which were lower in the pecking order) were able to eat. To be very clear, I stopped ALL restrictions during their molt and the winter, because they dropped weight anyway.
This was only a problem during my hen's first year. Now, they're all maintaining a healthy weight and I NEVER have problems with overeating anymore. So, I have no idea what caused the Great Gluttony Epidemic of '21, but the hens seem ok now. Also, just a note, but I actually use New Country Organics Corn-Free Layer Feed now to cut down on the amount of calories during the summer months (they don't need their food so calorically dense when it's hot). I use the corn version during the winter and molting season. Hoping you can figure something out!
Edit: I wanted to add that I never went by weight when judging who was fat. This was because a few of my fatter hens weighed the same as a hen that was in perfect shape (she's a taller hen with larger bones). I always felt the keel bone, running my finger all the way down to their abdomen. Hens will naturally store any excess fat in their abdomen, but it's when there is an exaggerated pad of fat in between your finger and the end of the keel bone (erm...the butt-bone?) that you know there's a problem. My hens are fine now so I rarely feel this anymore, but it really is like a pad of smooshiness, stopping you from feeling the "butt-bone." Definitely try feeling your skinnier hens to understand exactly what you're trying to find. Some of my perfectly healthy hens had a little bit of fat there, but you could still feel the bone.
