If you can post a photo, we can tell what breeds they are if that's of any use. Silver Appleyard come as large (normal) and miniature so I wonder whether you've got a mixed bag. I've got the large ones and they are big - I now look at wild ducks and think they're tiny. But they are also brilliant egg layers, don't go broody and good for meat if you need it. If I was you, I'd get rid of the two little drakes and keep the big trio if they are all large Silver Appleyards.
H