Let’s talk about blue eggs

I have a Lavender Ameraucana that I assume laid all these eggs in order from left to right. No filters.The last one is the most brilliant shade of turquoise I’ve even seen from any of my hens! (Side note: I also have a 12 year old EE, but I’m pretty sure she’s not laying). I haven’t seen another blue egg in a few days, but I’m anxiously waiting to see what’s next.

Question: Does anyone else see a range like this from one hen? Any idea what makes them more turquoise? Is it something they’re eating? Recently we’ve given some different treats like water melon, spaghetti squash and Raisin Bran.