You need to supervise the ipad. Or, you have the employee sign a form when given out that their last paycheck will be docked to replace non-functioning ipads.
"This document offers guidance on some important considerations for getting the most out of your iOS deployment." Covers: Prepare your infrastructure. Set up devices. Configure and manage devices. Deploy apps and content. Plan for support.
https://www.apple.com/business/docs/iOS_Enterprise_Deployment_Overview.pdf
Quick overview of zero touch deplayment
http://www.apple.com/education/it/dep/
Consider DEP, Device Enrollment Program. Use VPP, Volume Purchase Program. Select an MDM, Mobile Device Management.
Overview of ipad & iphone deployment.
It's education focused.
http://www.apple.com/education/it/
Writing you own app for your business:
https://developer.apple.com/enterprise/
MDM -- Mobile Device Management
Airwatch, Apple Configurator with Apple Profile Manager, GroundControl, Meraki -- is free, MobileIron, or Zenprise
https://developer.apple.com/videos/play/wwdc2015-301/
For a comparison see this page:
http://www.enterpriseios.com/wiki/Comparison_MDM_Providers
VPP -- Volume Purchase Program
http://www.apple.com/business/vpp/
http://www.apple.com/education/it/vpp/