Are these eggs from the same chicken?

So we added a new chicken to our flock knowing that she was already laying; our other hens hadn't started laying yet. The egg on the left is the first egg she gave us... at least I'm assuming it's from her because it looks like the eggs that were shown to us when we bought her. She's a buff orpington, so the eggs are darker than I expected. Now every other day, we get one egg. The progress moves from left to right in the picture. Each egg gets layed in alternating nest boxes (we have two). The buff orp, Fern, was likely stressed on arrival because the lead hen kept pecking at her, but that's stopped now. So I'm wondering if stress made her eggs smaller and less dark, and now she's recovering and they're getting bigger and darker again...or if one of our other chickens has started laying. We have a light brahma, barred rock, and blue laced red wyandotte, all of which should start laying anytime. Thanks!

And we are SOOO excited to finally have eggs! I had my first set of scrambled eggs this morning. Yum!