According to the Universities Federation for Animal Welfare, around 18 per cent of piglets do not survive until weaning in the UK (48). Death can be due to several factors such as chilling, starvation, disease, over-lying/crushing and cannibalism by the sow. The farrowing crate is supposedly used to prevent sows from accidentally crushing their piglets. In fact, the danger of crushing is a direct consequence of factory farming techniques and the confinement of a crate, which is exasperated by the increasing size of sows, and lack of bedding materials which causes a large amount of stress and frustration to the sow as she is not able to perform natural behaviours. Three quarters of the crushing occurs in the first 48 hours after birth, so even if you were an advocate of crating sows – confinement cannot be argued for after that time.
Piglet mortality is roughly the same on outdoor units as indoor units in Britain (50). Also, an analysis of data from Swiss farms has found that piglet mortalities in farms using loose farrowing systems were no higher than those in farms that used crates (51). Commercial farrowing systems predominantly operate indoor confinement crates or outdoor arks, which represent the two extremes of sow restraint, substrate provision and environmental control. The ‘Volkenroder Pen’ in Germany has been shown to reduce piglet mortality to 11 per cent from 17 per cent (52).
In any farrowing system, most deaths occur during the first few hours of life, either from crushing (overlying or trampling) or from hypothermia or starvation, or both. It is unlikely to be possible to design a system in which piglets can suckle with absolutely no risk of crushing. However, any factor which limits piglets’ ability to suck freely, such as obstructing bars or an inability of the sow to present the udder conveniently, is likely to increase morbidity and mortality of piglets (16). Easier access to the udder might reduce aggression also (16). Savaging, where sows attack and kill their own piglets, is reported to be less common in free farrowing than in confined systems (16).
It has long been argued, even by sectors of the pig industry, that alternative indoor systems are “as commercially viable as traditional crates” (53).
It is vital to recognise that the crushing of piglets by their mothers is an unnatural phenomenon, and it is evoked by modern farming techniques. Modern pigs are selectively bred to give birth to nine to 12 piglets, instead of four to seven, which is unnatural. Wild boars do not kill their own piglets, partly because they give birth to fewer piglets and can build nests to protect the piglets. The crushing of piglets is a direct result of the way pigs are farmed.