Like many working dogs in Australia, German coolies (or koolies) are dingo-like in temperament and behaviour. Unusually, koolies can also be trained to be perfect chook guardians.
Lucy comes from a stud breeding 'soft' dogs to work sheep without frightening them. Apart from her basic instincts for softness she's also been bred for intelligence.
This dog taught herself to 'stay' when I suddenly shouted at her when she got between me and some sheep. She dropped to the ground and was still crouched there ten minutes later. Ever since then she's understood 'stay'.
For her to learn to respect chickens (and chicks) took one very short lesson when she was 4 months of age. She heard the word 'no' and instantly understood that the chooks were family. This was because she had already put her complete faith in me as boss. This is the kind of dog you need around chickens: soft natured and dedicated to pleasing her owner.
It probably also helps that she's incredibly maternal. I'm not sure if the males of the breed would be quite so reliable around chickens or kids, but Lucy is strongly protective of young animals.
There are a few other breeds with some of these traits (such as miniature fox terriers, if you buy the right strain) but few combine fox deterrence, guarding the home from strangers, and rat disposal with such reliability around vulnerable members of the family.
I know I would have lost chooks to foxes without my koolie. Thank you Lucy!