Hello Duck Rogers and welcome to the group
This is predominantly a UK forum I think but we have members far and wide.
I am assuming you are looking to get a house duck? Great you are doing research first

Apologies if I have the wrong end of the stick but I will continue this post in regard to a single house duck.
Ducks are flock animals as such prefer to spend their days with other duckies rather than being alone. A single duck will be a miserable duck sadly and although (thanks to the 'Friends' phenomena) some people in the USA have single house ducks, it really isnt in the best interest of the duck.
Interesting question about the window. Light is very important to all birds, ducks especially. They need to get at LEAST 15 minutes of natural light outdoors (not through a window) to be able to synthesise some of their vitamin requirements.
Ducks also spend the majority of their day foraging, if you have an indoor duck then it wont have any foraging opportunity and this may create problems for the duck. They are also extremely mucky, pooping every 15 minutes or so.
Duckies may also suffer being inside as they cant cope with warm temperatures very well and irregular light patterns can cause problems with their reproductive systems.
If you end up with a fella, you also have to consider aggression issues which will come when he matures.
There are many reasons why a single house duck isnt a good idea for you and the duck.
BUT if you do want ducks and you can house them outside in a group of at least 2/3 then they are truly wonderful animals that give a huge amount of pleasure!
Please feel free to ask lots of questions!
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