Takes a while for the old feathers to fall out and new ones to grow in, during which time they need protein for feathers, leaving none to spare for eggs. So, a couple of months isn't unusual.
However, the good news is that, when they start to lay again, their eggs will be bigger and, as the days lengthen in the spring, they'll be putting out eggs like gangbusters!
It's a bad news / good news kinda thing. But, the rest from laying is good for their little bodies.
Hope this helps.
