Sorry about the old pic-I have none of the new pics loaded

I brought these 4 home on March 1st and can only guess they were about 3 or 4 days old since ducklings/chicks are bought out within days at our TSC. That would make them 3 weeks old yesterday. All 4 have a lot of their feathers in, they started getting them just over a week ago. I read that they may be feathering a little early since they have been swimming everyday since I brought them home (always supervised, dried, and kept warm). The 4 are mostly alike in size, but I would have to say Mose & Doc are slightly smaller. Questions:
Thanks for any help!!!
I brought these 4 home on March 1st and can only guess they were about 3 or 4 days old since ducklings/chicks are bought out within days at our TSC. That would make them 3 weeks old yesterday. All 4 have a lot of their feathers in, they started getting them just over a week ago. I read that they may be feathering a little early since they have been swimming everyday since I brought them home (always supervised, dried, and kept warm). The 4 are mostly alike in size, but I would have to say Mose & Doc are slightly smaller. Questions:
- Daphne (yellow turning black) seems to sit a LOT. She eats, drinks, walks and swims normally, but is often sitting. They eat chick starter and I add the 100mg regular Niacin to the water. She is also the friendliest of the 4 and the loudest! Should I be concerned about all her sitting?
- When can they live outside? I am in NO rush to get them out and their outdoor home will not even be ready for at least another week. They will have a run safe from predators and within it a protected 'house. Right now our temps here are mid-high 60's during the day and evenings in the 50's. Like I said, all 4 are pretty feathered already.
- While I THINK Daphne is a female (simply because of the mind-boggling volume of her peeps), I have no idea with the other 3. I know their Quacks won't start for a few weeks (Niles is trying to quack and it is adorable!). If it turns out I have 2 or 3 drakes, how long do I have before this becomes a problem for the female(s)? We will be ordering 4-8 females from Metzers but that means new ducklings being raised and then integrated in with the current peeps.
Thanks for any help!!!