I have three adult ducks (1 pekin and 2 khaki Campbells), and I did have 6 pekin ducklings which were about 6 weeks old. 1 of the 6 was born with either a heart problem or respiratory problem as it was very sleepy to begin with and could never squeak or quack, high respiratory rate, so it was probably about a third of the size of the others. I decided last week to put them in paddock with adult ducks to enjoy pond and grass. I thought the little one would be alright since it was a lot bigger than a newly hatched duckling. I came back after an hour and found it headless with no insides. I had seen the crow hanging around when I first left but thought it would be big enough. Anyway the other 5 are pretty much as big as the khaki Campbell’s and yesterday I found one had it’s eye pecked out and a hole just above it’s beak down to bone... it seems alright now, I hope it will be ok. I’ve got them locked up but I don’t understand why the other 3 are fine but it keeps going after the large ducklings. Every time I turn my back it’s back over there.