The others have answered most of your questions pretty well, so I won't cover them again. But depending on the age of the lamb you will still need to feed it milk from a bottle. You will need to go to a stock/animal feed store and buy a bag of powdered milk. One 20kg bag should be enough for a single lamb until weaning (about 4-5 months old). You will also need to feed it a combination of feed - so green pasture, dry feed (hay) and grain. Otherwise if you have a sheep that only eats green pasture, they won't get a balanced diet and you will find that they will be constantly scouring (liquid poo). You will also need to give it some mineral supplements - a salt block/lick or a granulated mix.

the other thing is, you want one for a pet. What are you going to do with it as an adult? Like any pet they are for life and not just for "christmas'' LOL. An adult poddy is the biggest pain the ass you will ever see. They will ruin fences, they will eat everything they are not supposed to eat, like your garden and trees. They will knock the kids over and be a general nuisance. You will have to be prepared to have it shorn once a year, you will also need to have it crutched every few months - especially if it does get a bit ****ty around the rump. Crutching is just where they shear around the backside and down the back legs to help prevent fly strike. Mulesing is where they actually take off the skin around the rump.

Other things you will need to know
Fly strike not only occurs around the tail end - a sheep can get fly strike anywhere on it's body. You will need to be prepared to check it regularly all year round for flies. You will need to be able to treat it if it does get flies - either by having someone who can come out that day and treat it or treat it yourself with a combination of cutting back all the wool on the affected area and putting a treatment on the area to kill the maggots. A sheep can be dead within a week if flystrike is left untreated. the longer it goes on the harder it is for the animal to recover from it.

If you are planning on keeping it in the same small area, you increase the chance that they will be affected by worms and other parasites. You MUST be able to provide a rotation of paddocks. Not only for the parasite control, but also so they get fresh feed and to allow the feed to recover.

Long term, they are not great pets. To be perfectly honest, it kinda ****s me when people think that they are a good pet because they just aren't. it isn't just a low maintenance animal that you can stick out in a paddock and let it fend for itself. they are a lot higher maintenance than people think they are. ATM, we are feeding our sheep feed, hay and mineral supplements every second day. During summer DH drives around and checks them every single day for flystrike. Even though we use preventative measures such as drench or clik, they can still be prone to flies if the weather conditions are right.