All chats are being allocated equally over your operators by default.

Allocation will be randomized among operators with the same chat load (=amount of active chats).

However, there are several factors that will influence the allocation behaviour:

1. Chat Button Settings
   You can set a target operator / group for each of your chat buttons under Link Generator -> Advanced (which may be confusing when forgotten).
   
   
2. Groups
   If you have different groups you allow your website visitor to choose from, the group selection will to take precedence over the operator's chat load.
   
   
3. Cookies
   Each website visitor will remember the operator he was initially talking to. If website visitor ABC was allocated to operator XYZ once, he will always try to connect to XYZ unless XYZ is not available.
   You can deactivate this behaviour under Server Configuration -> Chats.
   
   

Please note: If you want all operators to receive incoming chat requests (=no allocation), you can set this up under Server Configuration -> Chats.