At night, I use a flashlight to herd ducks where you want them to go. Don't shine it in their eyes, but just to one side, like you would use the bamboo pole to guide them in....works on the Mallard derived ducks. Muscovy are about like herding cats or goats- it ain't happen'n!! They (Muscovy) respond better to being led with treats to where ever you want them to go. Like others have mentioned, ducks get treats when they go where they are supposed to go. If you are just starting out with them, I would keep them penned a few days, then start letting them out a couple hours before dark. It can also be helpful to put a small cage inside your pen and put a couple of the ducks in there before you let the others out. Then, they will want to go back in the larger pen to be with two ducks in the cage. After a few days you can let everyone out when all get the hang of going back into the larger pen.
I have to get secure place to lock up my Muscovy as we are putting a new roof on the house. Females are used to roosting on the roof and the rest are safe on the ground in our fenced yard with three LGD keeping predators out. But, with new roof (nice, red, shiny!!) it is either clip wings or pen at night.
And, I have to get a place to put my Black Copper and Blue Copper Marans.... so time to build a bigger poultry house!
Donna
Dandridge, TN USA