new duckling almost drown by older one

[Bent Fork Farm]

I picked up this duckling today , the woman who sold "sqeaky" to me said she was ready to stay outside and it should be no problem introducing her to our other ducks. Once this ducky got into the pond, the larger, older pekin grabbed her neck and tried to drown her! Help...how do I integrate all of them together so there is no fighting or drowning?

 

[Kevin565]

How old are your other ducks?

 

[Bent Fork Farm]

The others are almost a year old. I built this little playpen for sqeaky 2 days ago , she wants to play with the others so bad, I let her out to mingle with them yesterday...she follows them just as she is supposed to ...but the big white peking "Stelli" just dunks her/him under water, and grabs her/him neck with it's beak. Someone suggested i give them all snacks at the same time...I am afraid stelli will hurt sqeaky. thoughts?