I thought egg-laying was a function of day length, among other things. In other words, if those hens have their "daylight" extended by artificail light that egg yields (number of eggs laid) per hen could increase 10-20 %. Maybe it's just Karli Rae's skill in raising layers. Maybe she sings to them softly...

Hush little hen,
Now lay me an egg.
Don't make me plead,
And don't make me beg.
If you don't,
I'm telling you,
I'm look forward,
To chicken stew...

I suspect that good nurturing is more likely than threats.