Carcassonne rules
Mid-game arguments about farms, pigs and builders, answered one at a time.
Pick the thing you are arguing about. Each answer says which box the rule comes from, because half of them are from expansions.
The pig
You may place the pig only on a field where you already have a farmer. It is not a follower, it never scores on its own, and it cannot be moved or returned.
At the end of the game, a field holding your farmer and your pig pays 4 points per completed city touching that field, instead of the usual 3. The pig stays on the board for the rest of the game, exactly like the farmer.
If you lose the majority on that field, the pig does nothing for you. It boosts your score on that field, it does not win it.
Farms: who scores a field
Farmers score only at the very end of the game, and they never come back to your supply.
A field is every stretch of grass connected without crossing a road, a city wall or the edge of the tiles. Whoever has the most farmers on that field scores 3 points for each completed city that touches it. A tie means both players score the full amount.
Cities that were never finished are worth nothing to farmers. A single field can touch several cities, and one city can pay several different fields.
The builder: taking a second turn
Place the builder on a road or a city you already occupy with a follower. It is not a follower and does not count for majority.
When you later place a tile that extends the feature the builder is on, you immediately take another tile and play a full extra turn. You get at most one extra turn per turn, and if the second tile also extends it, you do not get a third.
Cloisters
A cloister scores 9 points when all eight surrounding tiles are placed, and the follower comes back. Left unfinished at the end of the game, it scores 1 point for the cloister tile plus 1 for each neighbouring tile placed.
When is a road finished
A road is complete when both ends are closed. An end is a city gate, a cloister tile, a crossroads, or a tile where the road simply stops. A loop with no ends counts as complete once it joins up. Score 1 point per tile.
The big follower
The big follower counts as two followers when working out who has the majority. Everything else about it is normal: it goes on cities, roads, cloisters and fields, and it comes back when the feature scores.
Trade goods
When you complete a city containing wine, grain or cloth symbols, take one token for each symbol, whether or not you scored the city. At the end of the game, whoever holds the most of each of the three goods scores 10 points. Ties give all tied players the full 10.
Questions
Can I place the pig on a field where I have no farmer?
No. The pig only ever joins a field you already occupy, and it must be placed on the tile you have just laid.
Does the pig help if I lose the field?
No. It raises the value of a field you win from 3 to 4 points per completed city. If someone else has the majority, it is worth nothing.
Can I put a farmer in a field late in the game?
Yes, and it is often the strongest move of the game. Placing into a big contested field on the last few tiles can swing thirty points.