Different aged pullets synchronized their first eggs!

Last summer I raised two different batches of chicks six weeks apart. Of the four older pullets, two are EE's, and out of the younger batch of three, one is an EE.

The first EE's are seven months old now, and I thought they'd never start laying! Then I started to suspect that they might be waiting for the younger one to catch up. And it appears that's exactly what's happened. Within days of each other, all three have laid their first olive-green eggs!

Only one of the older group of four has been laying, a GLWyandotte, for several weeks already. The others are slow-to-mature breeds, a Cochin and two Brahmas, so they may take a little while longer.

But I find it very interesting that all of the EE's have synchronized their egg debuts despite the different ages! Has anyone ever seen this happen?