Duck Weight?????????

As long as she looks healthy and active I would think she is fine. Maybe she was hatched from different stock which means she is slightly smaller.
Check she is bathing, clean head and eyes. If she becomes listless then consider she may have an internal problem, which a course of antibiotics, moving to a different area and ensuring a clean supply of water normally resolves

Thanks both for the responses, puts the mind at rest.

Hi Kate,
She started laying about 10-12 days ago, not boiled or fried an egg yet but both the royal iciing on the Christmas cake and our yorkshire puddings where courtesy of the ducks.
If it the other duck takes the same cycle with the crouching and filling out on her underside then i recon we will be having two eggs a day within 14 days!
I must admit i was well chuffed smiled for many hours, what clever girls they are!
Only problem is they wake up between 6.30 & 7.30 now which on ocassion is b4 our 2 year old son!!!!

Good luck with your girls anyway!