When to move ducklings?

[ChcknLady]

i have 3 4 day old ducks (1 pekin and 2 mallards) in a brooder with 2 chicks. How long should I keep the ducks in with the lamp and chicks before I move them out to their house outside? I live in Western Pa so it still gets really cold here at night (30's) and still only about 50-60 during the day.

 

[Brickman House]

I keep my guys in for 4 weeks, with temps around yours. I keep them in not so much for low temperatures (I'm really beginning to think my guys need a lot less heat than I give them), but more for size.

My duck yard is enclosed with a picket fence, and has a 250 gallon pond. It helps to have some size on the ducklings, so that I don't have to worry about them slipping through the fence, and so I'm sure they can get in and out of the pond.