Finally after a long struggle we have been able to complete the extension to move the chickens from the brooder to their final house. One major constraint we faced was with the cost of materials so we used alternatives, polyethene roofing instead of iron sheets and a mixture of burnt bricks/cement/sand as the flooring material instead of rock (to ensure the chickens do not scratch). 

On the first night however, due to transition stress and new environment, one of the chickens was crushed to death in a corner so we have to place bricks and plastic materials to change the corners to curves to prevent this happening again.

Photos of the migration below: