Since the 1960s intensive farming has expanded into industrial-scale units, with the use of vast sheds for poultry and egg production, as well as acres of polytunnels for market gardening, growing soft fruit or producing plants for garden centres. Industrial farming also includes fish hatcheries, where huge tanks of freshwater provide a suitable environment for the early stages of salmon or trout production. The smolts (young fish) have to be transported to off-shore fish farms to grow to full size before they can be harvested.
A typical group of poultry sheds at Drumshoreland Muir in West Lothian. These industrial-scale farming units are always noted on current OS maps.