Ducks won't use pond

[Eringm]

So my 2 ducks prefer to use a small rectangular tray to bath in when there's a perfectly good size pond which is easily accessible for them to get in and out of, why won't they use it.

I've put both of them in the pond but they just jump straight back out go back to the small box.

Why are they doing this ?

 

[redsoxs]

Are they the only two? And are they young? They may be unsure of the "scary" pond since an older duck hasn't shown them it's safe.

 

[Amiga]

So, this is a pond, not a kiddie pool, right? Is there a snapping turtle in the pond?