Hatching ducks under chickens??advise

[chipens]

I have muscovy ducks and am wanting a few more ladies but can't find any foe sale close atm.
But i have fertile eggs and broody hens coming out my ears.
I know it can be done. Just wanting the best info/advise, on how and dos and donts ect.
I have 2 maybe 3 broodys atm one is a small young hen.
The other is 1.5 yo barred rock but has a pendulous crop and wears a bra.
The third I found sitting today (not sure if actually broody) shes small but has hatched chicks before.
Who is my best bet at hatching and raising some ducklings?? Bigger hen or smaller?
Only going to do maybe 4-6 eggs? To try get 1 or 2 girls if I'm lucky.

I've let the ducks do it in the past but I end up with them in a brooder, they're terrible mothers.

 

[sourland]

If any of these hens has brooded successfully in the past, that is the one that I would pick. Some hens will not set the 5 weeks required for hatching Muscovy eggs so have a 'Plan B' in mind. Maybe put eggs under several of the hens hoping that one will go the necessary period of time.