gene expression to quantify the age and number of worms?

Dear all

I wonder if there is a gene expression technique used to describe the age and number of worms in a population at a given time?

I am interested in C. elegans population dynamics, in addition to counting the number of worms and stages on a petri dish I wonder if someone is using gene expression profiling to describe the a population of worms?

In advance, I will appreciate any thoughts and comments. This is not my area of expertise, but I can say that the idea of using gene expression is to increase the reproducibility, not the contrary.