Lazy chooks

Recently got 2 new hens - they settled in really quickly and started laying within a day or two of arrival... good girls!

My two older black rocks (about 4 years old) haven't started laying again this year yet... despite shaking the bag of 'layers' pellets at them and telling them to get a move on!

I know they slow down as they get older, but do you think that with the arrival of the two new girls they see their job as done and have gone into retirement?

Thanks Joyfull. I thought there was maybe a bit of egg envy too... between you and me, the new girl's eggs are larger - and it looks like Maud and Doris (the old girls) have been pecking at a few!