I am a new member, at present, my family has handed over a chicken coop with the size of 200 chickens, but I have no experience in raising chickens. I want to ask in such a large quantity, is it difficult to raise and manage? Do I need a lot of manpower? I am very worried.
You'll be carrying a lot of food and water to them-- something like 50 pounds of food and 25 gallons of water every single day. (Might be more, might be a bit less, depending on the kind of chickens and their ages and the weather. But it is going to be a large amount in any case.)
Cleaning is also a big job when you have that many.
With that many, it will be harder to see if any particular chicken has any problems, so you might have some die from problems you could have fixed if you noticed them in time.
If you are able, I suggest you get advice from the family member who handed over the chicken coop. For a coop that big, and that many chickens, there will be quite a few things that work really well if you use them right, but cause trouble if you do it wrong. For example, some feeders will clog up with one kind of feed but work perfectly with another kind. Some waterers leak and then run empty unless you do some simple thing (that isn't obvious until someone shows you.) Doors, lights, windows, fans, roosts, nests, bedding & manure management--I don't know what exact features that coop has, so I can't really tell you what to watch out for. I just know there are usually things that have to be done a certain way to work right.
Since you have no experience raising chickens, it might be easier to start with a smaller number of chickens first, rather than jumping right to 200. Maybe you could raise 25 or 50 chickens in that big chicken coop this year, and a larger amount next year after you see how it goes.