Good to hear your ladies are broody, Mom2emAll!
I would bet that the not-so-broody hen isn't quite ready to set. Normally they will amass at LEAST 12 eggs (most of mine like to hit around 18 or so at least), So she just may not be there yet. Also, if she was laying in the other hen's nest (communal nests are common with 'scovies) she may be behind and still going broody... leave the eggs there, she may still set. Alternately, she could have decided to move her nest spot - I had one do that midway through lay, once.
Well, turns out I have 8 eggs under the hen I thought had 6. The other hen has I think 18, the one in the barn has 10... and I took 13 eggs from the broody with a huge nest and put them in the incubator along with my goose eggs (except for 2 that were just too dirty)... leaving her with a whopping 21 eggs. Today another muscovy hen dug out a nest in the coop, so I bedded it with nice clean straw and put a cover over it, to keep any future eggs clean - the one that was in there were GROSS because the nest was under the chicken perches.
As for how I will care for them - easy! Well fed, free ranged, and well cared for until they are sold or butchered. I usually have NO trouble selling all the ducklings I can produce at 4.00 apeice. I can offer a nice variety of colors, so that helps Otherwise, any extras - we usually keep a few for ourselves anyways - go in our freezer. I almost always I keep more than what I 'need' and sell some as juveniles. Adults can be harder to sell, but if they don't sell as planned there is always the freezer.
If it turns out supply is exceeding demand, I have no trouble with picking up future eggs and selling them for eating eggs.
Oh, and trust me - if I didn't sell any ducks, with my approximately 15 adult hens I would have WAY more than 100 muscovies within a few years. Probably more like several hundreds, considering each hen will hatch about 2 nests of 20 eggs per SEASON... So potentially I guess I could have about 600 ducklings just this year. If they sell, I'll hatch - if they don't, I'll collect eggs instead.