What's going on?

I'm confused.  We have 9 chickens.  Six that lay brown eggs and three that lay green eggs.  Today and this past Wednesday our chickens gave us a total of 9 eggs, which is great.  Now here is where I get confused.  Each day we had 7 brown eggs and 2 green eggs.  What could be happening?  Do we have and Easter Egger who should be laying green eggs now giving us brown eggs?  Do we have a brown layer giving us 2 in one day?  I've read that chickens have 2 ovaries but one is usually dormant and that only one will be in operation. Maybe we have a chicken who is using both ovaries? An egg takes 21-25 hours to develop.  

Today's loot.

Here is how it happens

The first thing that forms is the yellow, or yolk, of the egg. This is formed within the reproductive organ of the bird or ovary. The yellow breaks out of the ovary and enters the upper end of the reproductive tract. Here, the white of the egg is added. It then travels down to the lower part of the tube where the membranes and the shell are applied around the yellow and the white.  It takes about 20 hours for the egg shell to form. If the hen lays brown eggs, the brown pigments are added to the shell in the last hours of shell formation.  The color is dependent on the breed.

I still find this so fascinating!

What do you think?