The saying "each dog barks in his own yard" is a metaphor meaning people are most comfortable and confident in their own familiar territory or area of expertise.
Breaking It Down
- Dogs: Represent individuals.
- Barking: Expressing opinions or criticism.
- Own yard: Their domain or comfort zone.
Essentially, people tend to be more vocal where they feel confident and less likely to comment where they feel uncertain. This is natural and not necessarily negative.