Your view: Can readers crack the puzzle of this double yolk egg calculation?

As per custom and practice, I recently bought a half dozen extra large eggs from Stocksbridge Co-op and upon cracking open two of them, I was consequently surprised to see that both of the said eggs had double yolks.

Similarly a few days later I repeated the process and once again found both eggs to have a double yolk, as did the fifth one I cracked open for frying the following day.

Thereby leaving me wondering (a) as to what the odds are against getting one egg with a double yolk, let alone five such from the same half dozen box and (b) whether or not the same hen would be responsible for laying them; and if so over what time scale.

Hence I was wondering if any readers could shed any explanatory light.

Meanwhile, I’m now wondering if the remaining sixth egg will prove to be a double yolk as well? And if it does, how that will affect the calculations.