Your opinion Please-on who laid this egg?

[TerriLaChicks]

I have 4 ducks.
Graham is 1/2 runner & 1/2 khaki campbell.
Ritz is 1/2 runner & 1/2 pekin.
Both of these girls were hatched last summer.
Sally & Slim are a matched pair of runners from Holderread's, shipped here about 3 months ago, fully mature.

I've been getting 2 off-white large eggs a day for a couple of months now.

Today, I got a slightly smaller (but still large by chicken standards), beautiful aqua-green egg-- laid in the duck pool! (kiddie pool)--first time that's happened!

Who do who think laid it? any opinions would be greatly appreciated!
Regardless, I will be putting these eggs to hatch as soon as my good hen Myrtle goes broody this spring!

Evidently, the ducks only lay at night---is this normal? anybody know how to tell who laid what egg? Please help!

 

[momma's chickens]

I don't know who laid the egg but it is perfectly normal for ducks to lay very early in the morning, so early it seems like in the middle of the night. n

 

[goosedragon]

I would GUESS the new egg came from the newer runner duck (matched pair = duck & drake right?) reasoning the two half breeds are larger and could be laying larger eggs. The small pool layer was probably a first timer and you old ducks never pulled that trick before.