Spawn chunks, a 16x16 set of chunks around the world spawn, are always loaded, so you can use that to your advantage when making automatic farms.

How many chunks away are loaded?

In multiplayer mode, a grid with a default inradius of 10 (for a total of 21x21 or 441) chunks is loaded around each player and sent to the player by default, although this can be configured to be between 3 and 15, usually only lowered with a poor connection home server.

Are chunks always loaded in servers?

Although spawn chunks are usually kept loaded at all times, new spawn chunks won't be loaded by this command until a player moves within range.