The reason morning light works better is that the hens are still getting the required hours of light...day just 'starts' earlier.
With PM lighting, it simulates the daylight hours, but the timer clicks OFF long after it is naturally dark.
In one instant, it goes from full 'daylight' to total darkness. BANG!
Chickens do not see well in the dark. They will stumble around in the dark, get confused, and cause themselves to panic.
Their simple minds do not work well in extraordinary conditions...panic causes stress...stress leads to many health issues.
I do NOT recommend artificial light, as it does shorten their lives (laying and actual lives).
It is something used mostly in the commercial egg industry, where a chicken's life is measured in dollars and cents.
Hopefully, we in
permaculture, think of hens as more than a sum of pennies.
It was mentioned above that hens were not bubblegum machines. In reality, they are close to one.
Each hen is born with a quota of eggs. Once they have all been laid, she is 'Empty'.
In nature, it can take many years to 'empty' her. With artificial means, we can empty her in a couple of years.