Charlie's eggs

What should the eggs be like??

Charlie Croaker is one of my sussex.  I always know when she has laid because her eggs are rounded, white mottled.  They are very hard and look like they are covered in calcuim, this doesn't wipe off.  

The other susses lays completly different eggs hers are long, thin, and quite pale looking like I would expect from a sussex!!!

Which one has got it a bit wrong???  Or is this common for the same type to lay different?