What is the difference between a factory farm and a mega farm Q

Send to Compassion in World farming for review.

This is UK specific
The media use both terms
Factory farms have high stocking densities and cramped conditions
- A common condition is that animals are kept inside their whole lives. In the UK this is sometimes called "zero grazing".
- We can't get good information on the % of animals kept under various stocking densities, but can get data on % of animals kept inside for large amounts of their lives.
Mega farms are defined by size: either we use the DEFRA permit system or the US definition of a CAFO:
- cows: 700 dairy or 1000 beef
For cows there isn't a difference
Estimates of % of pigs on mega farms and factory farms differ a lot.
The distinction matters: only mega farms are tracked by DEFRA. It is very hard to find good data on factory farms.
We don't really know how many
All megafarms are probably factory farms, but not all factory farms are mega farms.

For pigs, we have 1.3M/5.1M pigs (2022 numbers) on EPR farms that's 25.5% WAP 2024, P28

1.3/5.1
4781015/((4575334/0.96)+(205,691/.6))

However, 96% of fattening (aka "finishing") pigs and 60% of breeding sows are kept in conditions we might describe as factory farm conditions: sows kept in farrowing crates for 5 weeks of every pregnancy, so a quarter of the year. References from WAP, 2024

For broilers we have 85-95% on factory farms

For layers "defra data" suggests 23% enriched cages, 13% in barns and the other 64% free range (WAP 2024, p35).

WAP 2024 p27 say that 96.5% of poultry meat production in 2023 came from non-free range.