How long does it take for their feathers to grow back and for them to start laying eggs again? (I guess... how long does "molt season" last?)
When I was feeding an 18% Protein feed my Barred Rocks quit laying for about 5 weeks on average and molt completion about 6 weeks average.
My Golden Comets slowed laying, but never stopped and they did a slow molt over a few months.
My 4 ISA Browns (16 months old) have also started a slow molt without slowing egg production yet, 27/28 weekly.
They are on a 16% Protein layer feed.
My Pullets (4 months old tomorrow) are still on a Starter-Grower feed 18%.
Chickens in my climate eat about 50% more feed during winter season so they are consuming 50% more Protein that's in a 16% feed.
So they are eating 24 Grams of Protein daily in winter compared to 18 Grams during summer season.
Egg production slows during a slow molt or stops during a hard molt.
So they save 6 to 8 Grams of Protein daily if they aren't laying an egg. Large egg 6 Grams of protein, Jumbo 8 Grams.
So between the extra feed consumption 50% more and not laying during a hard molt, they have 12 to 14 Grams of extra Protein daily for feather regrowth.
No need to feed a higher Protein feed during molting in my opinion.
I will see how my ISA Browns do during their molt on a 16% feed.
My Pullets will get transitioned to a Layer feed when one of each breed start to lay after 18 weeks. GC