Multiple roosters

[Attack Chicken]

Jez!!!poor hen lol

 

[gritsar]

If you are going to thin it down to two roosters for 40 or so hens there's no need to seperate the roosters. If you choose to keep the extra roos, more than the two, then you can build the extras a bachelor house.
I don't see any reason to seperate the flock. They've probably got their pecking order in good running order. In building a coop you need to have at least 4 sq. ft. per chicken, a little less for bantams. Generally the bigger their space the less issues you have with fighting and pecking.
Regarding your egg count, sounds like you need to be checking for hidden eggs. The decrease in daylight with the change of seasons can also slow egg production; as can their moulting.

 

[EurekaSouth]

At one time we had 3 roos and 11 hens. The roos just wore out all of the hens, but especially the ones that were the most accommodating. The ones that were very sweet and friendly to me (my buff orps and two of my RIRs) got it the worst - I ended up getting rid of two roos and putting chicken saddles on the bare-backed ones. We're all fine, now.