1000 acres - for crop, typically located in our hot and dry areas - is a hobby farm. 1000 acres in the wetter and greener areas running dairy cattle could be more commercial (but I lack experience there). The people I know running commercial farms are 10,000+ hectares.

What pulls up the average would be our cattle stations (ranches for the Americans) if they count as farms. These are huge - eg. Big ones 2-6 million acres.