I would like to get 4 Kaki Campbells to raise for eggs. My plan is to have a coop/run close to what I built for the chickens.( 1/2 hardware cloth / concrete pavers/tin roof).  I plan on to free range
them after 9 am or so and lock up in coop/run pm. What am I getting into? I do have 9 white legs horns chickens which are doing great. I do have a pond for them. What am I getting into?
so far.

I don't have any information on ducks, however, BYC does.  Enter "raising ducks" into the search box, there's about 10 pages of results.

I've had meat ducks for 7 years. I love ducks. They need a sacrifice area as they get messy. They also destroy their water in a couple hours. I use a small kids pool and dump it every few days and refill. I've always wanted to do a downspout thing that goes right to the pool but never got off my ass and did it. btw when the kids pool develops a leak jeep it and make put the new one inside it and use the old one as the outside armor to protect the new one.

So a wood chip or gravel area with kids pool. You'll also have to teach them to go to bed. The will want to have pool parties all night. Mine eventually started getting taken by an owl and they learned to go to bed after the second attack. Now they have trained new generations to go to bed. Like with chickens you should really have a boy, he will watch the sky for eagles etc. and signal everyone to cover. Having some cover in your free range area is also a good idea.

adding a multi vitamin and a C to their water will help keep them laying strongly year round.

The pond thing is tough.  Try to get them out of it at night.  I don’t let mine go there anymore and they don’t try since Lucky ?? got killed by a coon. They stick to a pattern in the yard.  I dug a hole by a frost free and make a puddle for them.  When in the barn there is a sump pit and kiddie pool with a hose on a timer to flush daily.  Works well. I am only there 3-4 nights per week to care for them.  I like them.

Had them for a dozen years, but usually only 2-4 hens.
They had a shallow rubber water bowl, maybe 24" in diameter.
Put 5 gal in every morning.

Mostly used eggs for baking.

My dad had some ducks.  They seemed to do as the chickens did, even sat on four chicken eggs and brought the chicks up.  Getting them out of the pond could be an issue.  He got lazy about their wings and they took off with some other ducks that were passing by one day.

I've got some ducks in the coop with my chickens. I've got a stock tank in there, and it's become all the birds' water source. I leave the garden hose in it, and have a timer for it. Once a day or every other day I set the timer for 2 hours and let the tank overflow all the shit out of the tank. In winter, I put a board over the top of the tank and I've got some holes cut in the board so the birds can get their heads in there for a drink.

Ducks are messy messy messy nasty gross and cover everything in shit. But they are a lot of fun. Also, they lay their eggs wherever, so I haven't found a duck egg in about a month... I've only got 3 hens and 1 drake though.

They're messy as shit, especially in winter.

The one thing that hasn't been mentioned is baby ducks. If you haven't been around them they are some of the cutest things on earth, in case you have kids. They will also imprint on you when they are young. Catch them newborn and handle them, and they will follow you around like a puppy. As far as they are concerned you are their parent. Just be careful, my ex had one like that and she made a quick turn while walking one day and stepped on it.

If you haven't, you may want to try the eggs first. That tubby, hippy Australian garden guy on youtube got ducks for eggs, and ended up not liking the eggs. He's shared a few recipes of the food he eats, and they're often really terrible looking, so, if they were too bad for him, I'd definitely want to try them first.

the main issue with ducks is they don't usually lay eggs in the same spot they just pop them out wherever they are. So if they're out of the coop most of the day you will have a hard time getting eggs out of them consistently.

If you have a dog, that dog might just follow them around waiting for a tasty snack (aussie does that at our place)

We locked ours in at night, and most layed in there.
One made a small depression under a low cedar and always layed there.

A friend gave me some of her duck eggs.  I'd never tried them before and they were delicious.  I made an egg sandwich for myself, and shared some deviled eggs with a couple of co-workers.  They were hesitant at first, but really liked them.

After I tried them I wondered why ducks aren't commercially raised for eggs.  Maybe consumers would have a hard time accepting the idea.  All the advice here makes me think it's because ducks can fly, and it would be too much work to keep thousands of wings clipped.

We've got 10 and get 5-10 eggs a day everyday.
No drakes.
They free range during the day and we lock them up at night.
I would say 80% of the eggs are in the coop in the morning the rest are always a fun time finding them.
If they make a nest you have to empty it of eggs for about two days in a row or they will lay there instead of the coop.
They are creatures of habit so they need a regular schedule. They don't care at all about me running a lawn mower or tractor next to them but if a strange car pulls up they high tail it for safety.
I have trained them to stay in about 2 acres of yard and a half acre pond (yes, they are pretty spoiled) but they are easily trained to stay in certain areas as long as they aren't desperate for food.
They have learned commands like "treats", "bedtime" and "bad ducks" much smarter than chickens.
They also keep the ticks down and control pests in my garden.

Bad part, as mentioned they are MESSY.
If you don't have space they will kill your grass in no time at all. If you have puddles they will kill the grass in that area partying in the water.
They get bumblefoot (a type of foot infection that can be fatal) if you have sharp stuff for them to walk on. (large gravel, thorn bushes)

If you have space and a pond, they pretty much take care of themselves.

I do have space and a pond. I do plan on locking them up at night and leaving them out to free range around 10 am. Food will
not be an issue for them. Them being  food could be an issue.

Look at runner ducks. They are pretty neat and aren’t into water. Coons got ours. We have 3 regular ducks and the6 started sitting on the eggs. Went out today and had 2 little ducklings

You'll have duck shit everywhere!

We have a few ducks and some chickens they all just live together. We let them free range and the whole group goes to the coop on their own before dark.

Ducks are fun to watch and I like the eggs, as has been mentioned they love splashing and swimming, and digging in any mud they can find. If you get little ducklings be sure to put them in the bathtub at least once, it's amazing how fast they can dart around in the water when they're still so awkward walking. Kids love them.

Relevant. He's cheesy but has good info: