Poetry motherland, what does it mean to have gold, silver, copper, iron and tin in the rooster's belly?

"Poetry of the Motherland" says that the rooster's stomach is full of gold, silver, copper, iron and tin.

I think:

"Rooster" refers to the outline of the motherland, not the motherland.

"Belly" may refer to the southwest hinterland of the motherland.

"Gold, silver, copper, iron and tin" refer to all kinds of minerals.

The southwest hinterland of the motherland is rich in mineral resources, especially "gold, silver, copper, iron, tin" and other metal mines.