The number of mega farms operating in Northern Ireland has rocketed in the last six years, new research has found.
There are currently 245 intensive factory farms scattered across the province.
Pig and poultry factory farms increased from 154 in 2011 to 259 in 2017 - a rise of 68%.
To be classed as intensive, a farm must have warehouses with more than 40,000 birds, 2,000 pigs or 750 breeding sows.
The research carried out by the Bureau of Investigative Journalism discovered that Co Tyrone has the fifth highest number of indoor reared livestock in the UK, with Co Antrim placed at eighth. The two counties have a combined total of 13.5 million animals reared indoors.
Critics have described the increase in mega farms as "worrying".
Emma Slawinski, director of campaigns at Compassion in World Farming, which created a hotspot map of the UK's mega farms, said the map displays a "worrying trend" of increased intensive farming practices.
"Northern Ireland in particular has two counties within the top ten of highest numbers of indoor reared livestock. Co Tyrone places at fifth and Co Antrim at eighth," she said.
"These animals will spend their lifetimes confined in systems that do not allow them to display their natural behaviours.
"These numbers and conditions are not acceptable and we need to address the manner in which we are farming these animals.
"To pack large numbers of livestock into cramped conditions may seem like a space-saving idea, but in fact it pays no regard to the animals' welfare, it promotes disease and illness, and it maintains the ineffective practice of feeding grain to animals, grains that could otherwise be used to feed our ever-growing population.
"What is perceived to be more efficient, is actually completely detrimental to the UK's standards of animal welfare, human health and our environment."
However, some farming experts say that intensive farming doesn't impact on animal welfare.
Ulster Farmers Union deputy president Ivor Ferguson said that such farms have to adhere to "strict" standards.
He said: "Family-run farms continue to be the norm in Northern Ireland but like any industry, in order to deal with volatility and changing market demands, some farm businesses have had to change course or diversify.
"Given the expansion of the poultry sector in Northern Ireland in recent years, the increase in poultry farms makes sense.
"While there are some larger, intensive family farms here, they are nowhere near the scale that is found in the US, China, South America, or even GB.
"To operate, intensive farms here have to adhere to strict environmental and animal health standards, including having at least one environmental audit each year. As a result, they are extremely efficient and deliver good environmental and welfare outcomes.
"Post-Brexit, one of our biggest concerns is that the safe, traceable, high quality food produced in Northern Ireland will be undermined by imports from countries with lower environmental, animal health and production standards such as the US and South America."
These mega farms require a permit to operate that is issued by the Northern Ireland Environment Agency.
The licence contains details of the farm operator, the number of livestock and set conditions.
A spokesman for the USPCA was also critical of the mega farms.
"Disease, lack of enrichment, housing issues, long distance and transport are all matters for concern," he said.