We are at war with the Clegg, a fearsome tribe of warriors. Both sides have typical medieval weaponry but explosives have not been invented yet. We are fighting over an area of fertile land that lies between our territories.
When passing through a small village we discovered the beginning of a small outbreak of zombie-ism. Our commander - a very intelligent fellow - discovered from the villagers how this worked - it is passed on by biting. He captured all the zombies and has brought them along. They are kept in secure zombie-proof steel cages that are transported on wheels. The commander can create new zombies by forcing prisoners against the bars to be bitten. There is a limit to how many cages he can transport.
The other side has no zombies - yet. Nor would they know what they were or how to use them - yet.
The commander wants to use zombies as war weapons.
A zombie army would be terrifying even to the most hardened opposition.
They would keep going until sufficient body parts had been hacked off to stop them moving forward.
By 'converting' enemy soldiers to zombies, they would increase their own numbers.
Unlike human solders, they need no food or supplies of any kind.
What method could our commander use to control the zombies enough to send them against the foes rather than attacking his own soldiers?
The Clegg have no knowledge of zombies. How can our commander ensure that the Clegg don't learn how to create and control their own zombies and mount a counter-attack?
Is there any point in our commander even trying? Should he just give up, destroy the zombies and carry on with conventional fighting?
Zombies will not attempt to bite or attack other zombies. They are only attracted towards live humans who they detect by sound and movement. They can walk or break into a shambling run.