Weaning duckings off of heat source

[Dace]

I have 4 khaki campbells that are 2 and a half weeks old. I just saw on another thread that they should be getting off the heat lamp soon. I understand the 5 degree drop per week for chicks but can someone tell me about ducklings?
At what temps can they go outside? I adore them but man are they messy!!

 

[toletiquesbysam]

Here's what I've read on it....
Supplementary heat may be needed for 5 to 6 weeks in cold weather; in summer, only 2 to 3 weeks. By 4 weeks of age, the ducklings should be feathered enough to be outdoors except in extremely cold, wet weather. High temperatures may result in slower feathering and growth.