Im sure the weather is very different between California and Canada at the moment- so each of you can really only make up your own minds about what is right for you and your ducklings. They are hardier than chickens- pick up a three week old duckling even with no lamp on in the brooder inside and their little bodies will be warmish- but put them outside in lower temps and they wont feel as warm.
Before leaving them out all night- try them outside during the day a few times to see how they go. Its easier to bring them back inside during the day and wait an extra week or so than to wake up to a very cold morning with sick ducklings from them being chilled.
Before leaving them out all night- try them outside during the day a few times to see how they go. Its easier to bring them back inside during the day and wait an extra week or so than to wake up to a very cold morning with sick ducklings from them being chilled.