If you have more than 2-3 printers on a cups server, you can easily make the load balancing (pooling) of print jobs using CUPS print queues.
a) First, create a class of printers. Go to the CUPS web interface to make these configurations http://server-ip:631/ or http://localhost:631/ if you are logged into the CUPS server.
b) Select the class tab to create one class.
c) Select printers for this class.
d) Select this class as the default (Default). From now on, the print jobs will be distributed evenly among all the printers in the class, through print queues. The hint is that CUPS handles all the printers belonging to a class as if they were one, making automatically load balance between them.