Solution
You can have the animal number printed as a barcode; go to:
[1. Animal Records] - [12. Settings] - [1. Sows]
'Sow Card' tab
In the 'Header Layout' or 'Footer' section, select the option 'Show sow number as barcode'.
Note: If you choose to print the sow number as a barcode, a human-readable animal number cannot be displayed in that same position.