Winter egg production issues

[pdau75]

I have 8 ISA brown hens and one rooster from hell. The coop is an 8' x 10' shed. I have a sunlight emulating light and I currently have the light running from 4a-6p. I searched the site a bit to see if I need it on for that long or to go on and off throughout the day. Also, I have a heat lamp in the coop. At what temperature do you recommend turning it on? Egg production is down 3-5 eggs a day...what else can I do to increase it to 7-8 a day? Much thanks in advance. Any other tips? Much thanks in advance

 

[ChickenCanoe]

You only need the light from about 4AM till dawn or until you let them out in the morning. Does it have windows?
Where are you located.
You might want to turn the heat lamp on at minus 20F but don't expect it to do much about the temp, they basically just heat what's in front of them.