G’Day from down under
cc67 
Welcome!
So, if I read this right ..
You have had your hens approximately 14 days.
There could have been a rooster at their previous location, so they could still have been laying fertile eggs when you got them.
BUT, you have collected the eggs every day and put them in the fridge with no hens sitting on eggs, yet they have fully developed chicks in them?
WOW .. that is bizarre!
If you find another one, can you take a picture?
I hope you enjoy being a BYC member. There are lots of friendly and very helpful folks here so not only is it overflowing with useful information it is also a great place to make friends and have some fun.