Ducks Swim?

[Debsbackyard123]

I am a new raiser of ducks and chickens. Both are three weeks old. The ducks have had a small pond in the brooder since week one. i put in a deeper one last week and now i am wondering when can they actually be placed in the pond. they would have access to land of course. It will also be fenced in. Their feathers are still growing but they seem to like the small pond but it is not big enough for all.
let me know what to do

thanks Debbie