Should I add more hens?

Right, I've got 2 black rocks and 2 lohmann browns. The black rocks are almost 4 years old and the other two are about six months old. The lohmann's I got about a month ago and have been consistently laying an egg a day each. The black rocks... I think I've had one egg from one of them so far this year.

So my questions are: am I too impatient for my black rocks to start laying again? Will they lay enough eggs this year to get a full '4 hen' quota? Should I get a couple more hens to get a full quota of eggs? (I have room in the hen house for a couple more).

I know the egg production will reduce the older the chooks get but should I get a couple more now, or wait 'til I'm sure production has gone down?

why not get more i mean this could be that last year for your rocks to lay they are old keep them though they might give you 1 egg every now and then