Eggs aplenty but from which birds?

At least three hens are now laying - obviously, since after couple of weeks of one or two eggs a day, we had three layed in one morning.

However, they were all the same size and colour - medium to large and mid-brown. I'd previously thought this was from a Maran as the Light Sussex eggs I used to get were much lighter. Now I'll have to scrap that theory.

Among the eggs layed in the first few weeks were one tiny egg, slightly darker in colour and about the size of a wood pigeon egg, and one huge egg - similar in every way to the others except that it was half as big again, weighing in at 96g (the others are around 60 - 65g).