Why has sow housing abandoned gestation crates in favor of large pens?

In automatic sow feeding and management systems, the traditional gestation crate is not used for sows; instead, large-pen group housing is used. This is mainly because under gestation crate housing conditions, sows get no exercise, which increases the risk of disease; the stress on sows during production is great, which can easily lead to embryonic death in early pregnancy; individual feeding amounts are not easy to control, resulting in uneven fat and thinness among sows within the group and poor group uniformity; and the requirements of animal welfare are not met. In the new food hygiene law of the European Union, which officially took effect on January 1, 2006, regulations on animal welfare were strengthened. These are all points worthy of attention for pig producers in China.
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Current conditions still cannot meet this~~~
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Raising sows in gestation crates has many drawbacks. But "individual feeding amounts are not easy to control" is also a shortcoming of gestation crates; saying so is a bit far-fetched, isn't it!
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Weigh input against returns. Advanced methods are all good, but ordinary people cannot afford the investment.
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I am currently making gestation crates and farrowing crates.