By the looks of your girls, you should be seeing eggs within the next couple of weeks and honestly, if they're singing the songs (none of my POL pullets squat for me and they've been laying for a few months now) and if they're taking interest in the nests you're closer than you think. Be on the lookout for yolk stained litter...I noticed that a couple of weeks before I started getting any eggs from my pullets. They were laying soft shelled, incomplete shells or even shell-less eggs and eating them a couple of weeks prior to me finding whole eggs.