CORRECTiON: TWO YEAR OLD Three year old hens not really laying

Yes. I've read the other threads and the excellent advice but sometimes there's one or two things about the question that's not like my situation....

I have three year old hens. There are two red sex links and one amber link.

They've seen quite a bit of predators take their fellow flock members and kept laying all through.

Then (last) winter hit and they all but stopped laying. They gradually started again in late spring...and never really picked up to where they were. I chalked it up to "age".

Then it slowed again. I'm not sure if it was around the same time or well before I put the new pullets in with them. I put in two ameraucanas and two tetra tints. The tetra tints have started laying.

So 7 birds total. There is enough space in the coop - but even so I let them into the run daily. The run is small (10X10) but there are perches for them, a 'dog house' for them to climb on top of and in and, a shelf. There's also a separate PVC run that is roughly 5x5 that I utilize to space out the chickens and to give them a chance to 'free range' safely.

The two red sex links seem kinda thin - not overly so. The amber link is still a fat bird.

They are all on layer feed (I offer some grower crumbles for the ameraucanas but everyone eats what they want). And I feed them scraps from the kitchen and occasionally make some brown rice or oatmeal or yogurt just for them.

What gives?