4/5 girls not laying

[want2know]

I have 5 chickens. Only one gives me eggs. The other four have not given me eggs since August. I've changed their food quite a few times. They free-range so they get tons of bugs. They will be two years old in April.

I was getting 1 from each (almost) everyday, and now nothing since August
I've done individual quarantine to see if I had an egg eater, but nothing. Each bird when in quarantine didn't lay, nor did any eggs appear.

My golden buff star is a champ and barely misses a day. They aren't stressed! They have a medium sided yard and they get tons of free time out and treats. I made them oatmeal the other day when it snowed. During the summer, I check the yard for eggs. Nothing. Now that it's winter, they stay in their run and I still don't see any eggs or remains if eggs.
Please help. I don't want to cull them.

I too, have 5 hens roughly around the same age. I live in south Texas, and none of mine laid for most of this month until 3 days ago, I have been getting one egg a day. In November, I was getting one or two eggs every couple days, nothing consistent. October was sparse as well. I would hold off culling until mid spring depending on where you are located. There are breeds of chickens that lay through the winter. My last flock, I had 3 sex-links and they all laid almost everyday all year long, but I had problems getting along with my newer chickens, so gave up constitent eggs for harmony in the flock.