There are many types of shills.
- Government agents (MI5, GCHQ, Police & local agents)
- Industry agents (such as Big Oil & Gas & Big P-Harma)
- Military agents like 77th Brigade (engaged by the Crown to identify dissenters online)
- Media agents (engaged by the owners of MSM to identify dissenters & to discover dirt to publish about them)
- Social Services & NHS employees (including your local GPs) who report anyone suspected of dissent, labelling them as mentally ill.
- Members of the public encouraged by government to report their neighbours.
- Ex-prisoners, disgraced police officers, ex army personnel are often offered a deal to work undercover.
The hierarchies are obscure but generally each shill has a handler to whom they report.
This type of employment is well paid.
Hence you will note that a suspected shill will disappear to make reports, will be able to afford expensive luxuries like cars, holidays abroad & have no visible source of income.
The name "shill" derives from "taking the shilling", a phrase denoting someone who is easily bought.
Further info: https://en.wikipedia.org/wiki/Shill