Pigs Kept for Breeding


Data on Pig Farming
Breeding Sows

Age at puberty (av.)28 weeks (7 mths)
Age when first bred 31.5 weeks (7.9 mths)
In oestrus for 3 weeks
Ovulates for 53 hours
Ovulates after giving birth 5 days after weaning
Type of cycle Polyoestrus all year
Gestation length 16.3 weeks
Fecundity Gilts av. 9 live born and sows av. 11 live born
Breeding life 2 litter/sow/yr BUT 2.5 in modern systems with longer day lengths. Sows killed at 3-5 years.


Age at puberty (av.) 28 weeks (7 mths)
Age when first bred 35 weeks (8.7 mths)
Breeding life Usually killed at 3-4 years
Sow/boar ratio 25 sows per boar is a 'practical ratio during mating'

Table from Lean (1)

The Farrowing Crate

Farmers boast that they no longer use metal-barred sow stalls, where pregnant sows spent their lives in almost total immobility, often chained to the floor. They don’t use them - because animal welfare groups forced the change through years of campaigning. Many farmers were against the ban. For example, a prominent Scottish pig producer, Keith Chalmers-Watson of Fenton Barns, N Berwick, had an intensive breeding unit and was in the pig industry for 70 years was extremely angry when sow stalls were banned and said: "Stalls are an extremely welfare friendly method of production and should still be available to us as a long term farming option."

The European Commission’s Scientific Veterinary Committee did not agree. It condemned sow stalls in a 1997 report because of the serious health and welfare problems. It stated sows in stalls have weaker bones and muscles, heart problems and more urinary tract infections.

Sow stalls were phased out over some years and became illegal in the UK from January 1999. This is not the case, however, in the rest of the EU where tethers (that chain sows to the floor of the stall) only will be banned from 2006.

Unfortunately the farrowing crate, a close cousin of the sow stall, is still in common use in Britain.

Exeter University, Survey of UK Pig Farming, 1998 states that 95% of Britain’s indoor pig units use farrowing crates. This means that there is no joy of motherhood for today’s breeding sow. She is caged and immobilised for 28 days at a time while she delivers and feeds her piglets.

The crate is fixed to a cold, bare concrete or metal floor. Bars little wider than her body make it a struggle for the sow to stand up or lie down. It is impossible to turn around. There is a creep area to the side of the crate where piglets huddle in what should be a warm, dry place.

Pregnancy should be a time of restless activity, of collecting sticks and leaves, of nest building. With not a strand of straw as comfort, her natural instincts are utterly frustrated. Sows may repeat the same futile gestures over and over again. Building an imaginary nest with imaginary materials for piglets she will never be allowed to mother properly.

Dr I Lean, Animal Production Dept., Wye College says:

“Under intensive conditions, the sow has little opportunity to exhibit the behaviour patterns which occur in more natural situations before and during parturition. The extreme restlessness commented on by many workers has led to a reevaluation of the type of accommodation provided for this time but has not so far led any changes in common commercial practice."

The bars prevent her from fulfilling any of her maternal instincts. At three weeks old her piglets are suddenly removed. The sow is given no treatment for drying her milk supply - except for reduced feed! She is made pregnant again, removed to a pen to wait until it is time to repeat the exercise. And it happens over and over again until her production levels drop or until she is killed through disease or lameness.

In 1999 and 2000, at Newham Farm in Cornwall, Viva! investigators saw caged pregnant and nursing sows smothered in faeces and flies, in a pitiable state. Alongside their living piglets were dead and decaying siblings, blackened and advanced in putrefaction. We registered complaints against the farmer but the authorities found nothing wrong with the place. Why? It could be because if they acted in this instance, they would have to take action against many other units in Britain.

It isn’t just individual farms who still use the farrowing crate. The biggest pig producer in the world, the Pig Improvement Company (PIC - formerly Dalgety), also subjects sows to this cruelty and we have filmed them, too. Their priorities are set out in the first heading of their booklet, Practical Farrowing Care & Sow Management. ‘Profit foremost’!

MAFF argue that the farrowing crate protects piglets from being flattened by their mother. Yet MAFF is fully aware that research shows that piglet death rates are almost exactly the same in non-crate systems. Industry publications report of alternatives that are successful in working farms. Furthermore, producers in many countries are already using alternative systems to the farrowing crate (52). Recent research shows that Solari pens, that release sows into a larger pen area a few days after giving birth, can be successful in protecting piglets.

Three quarters of crushing happens during the first 48 hours after birth, so - even if you were an advocate of crating sows - confinement cannot be argued for after that time.

Ben Bradshaw of MAFF states that: ‘piglet mortality in farrowing crates are approximately 8% to 14%; good alternative farrowing systems will need to have similar mortality rates.’ (53) A survey of 77 outdoor herds revealed the mortality rate to be between 11.7% to 12.3% (54). In fact the Meat and Livestock Commission’s own research consistently shows that a more natural system is equal or better than indoor crate systems. The MLC state that the mortality of pigs born outdoors is 11.2% against 11.7% for indoor pigs. Further, the death rate of the mother sows is much lower in outdoor systems - 3% against 5% indoors (54). In other words, it has been known for some years that piglet deaths are less in outdoor herds. (This is contrary to what the meat industry have maintained on media interviews with Viva!.)

Many would argue that this is yet another reason why factory farming should be banned. MAFF, predictably, state that they will not legislate to force all pig producers to breed in outdoor, free range systems. However, as already stated many countries use non-crate systems indoors. For example, the Volkenroder pen in Germany reduced piglet mortality to 11% from 17% in their crated farrowing systems (55). Some farmers in the UK have reduced mortality rates in non-crate systems to 5% by being present at every birth; other trials reported in Pig Farming magazine show eg that death rates in certain free-farrowing pens are no higher than crates on the same farms. Pig Farming (which supports intensive farming and the farrowing crate) states that one alternative indoor system is “as commercially viable as traditional crates.” (56) It does state that more research is needed - of course.

It’s vital to recognise that the crushing of piglets by their mothers is an unnatural phenomenon - created by modern farming techniques. MAFF have allowed modern pigs to be selectively bred to give birth to 10 to 12 piglets instead of 4 which is natural.

Wild boar do not kill their own piglets. This is partly because they give birth to fewer piglets and because of the way they build nests. If a mother rolls on her piglet, the baby would simply fall through the twigs and climb back in the nest. The crushing of piglets is a direct result of the way pigs are farmed.

Also, MAFF state that the piglet’s welfare is as important as the mothers. These words seem rather hollow when you consider that piglet’s fare better in outdoor systems and that MAFF permit early weaning which causes severe stress for mother and young.

Viva! is actively campaigning to ban the farrowing crate.


Piglets are born naked, with little hair, no fat, little liver glycogen reserves and poor disease immunity. It is essential that they are born into a warm, dry, clean environment so that they escape chilling and quickly find their mother's teats for colostrum. Certainly units filmed by Viva! were far from clean and in some the piglets were shivering as the heaters in the creep area were not on. Colostrum provides immune globulins which are directly absorbed prior to gut closure as well as being a rich energy source and gut stimulant. Piglets find their way to a teat straight after being born.

Indoor sow's milk is low in iron (because they can’t obtain it from soil) so piglets are injected with iron to stop anaemia. (57)


Weaning naturally occurs at 12 weeks but "such a lengthy lactation is inefficient because the lactating sow seldom comes on heat" (1), i.e. intensive production means sows must be made pregnant again as soon as possible - and by taking her piglets away, a sow comes on heat and can be made pregnant again.

Piglets can be weaned at one day and this has been practised but such animals need clean, warm surroundings and a feed similar to sow's milk. The costs have deterred producers from taking piglets this young (1). (Not the welfare implications!)

Most piglets are weaned at 21-24 days (22). (See Early Weaning in Mutilations section and Farrowing Crate and Disease sections).


Breeding boars are usually supplied by a breeding company who analyses the feed conversion, growth rate and carcass quality of siblings. They are usually selected at 6-8 months old and will start with 4-6 sows and as libido and fertility increases the ratio increases to about one boar per 25 sows. Young boars are often group housed in straw yards but incarcerated individually when older.


Gilts are selected for breeding on growth rate, feed conversion and reproductive history of their dams and sires and on their own anatomy. They used not to be bred at first oestrus but intensive production has changed this and now they are mated as early as possible. Contact with a male by sight, sound or smell triggers first oestrus. Gilts which fail to come in heat by 8 months are killed as are those 'unable to cope with housing conditions in an intensive unit.' (1)

Some farms synchronise oestrus in batches of sows by giving hormones. Gonadatropins stimulate oestrus and progestagens may also be used - synchronisation is adopted to avoid costs of staff being paid at night or weekends and to balance up litters - sows are injected with prostaglandin on the 111th day of gestation and farrowing occurs within 30 hours.

Artificial insemination was reported as 5% in 1994 (Pig Farming magazine).