Furthermore, migrating ascarid worm larvae proliferate under such conditions. It has been found that up to 15 percent of piglets will die between birth and weaning 8 and that 7 percent of pigs will die in the finishing pen. The use of slotted floors to allow excrement to fall into the manure pit causes many physical hardships for pigs. Uneven floors with gaps commonly cause injuries. Younger pigs' smaller legs get caught in the gaps and often break.
Females often develop nipple necrosis as a result of having their teats caught between the slots.
If the floor is metal, it is common for females to have their teats sliced off by the underside of the slot, which has sharp edges. Pigs raised in crowded confinement buildings are unable to move about freely or get any exercise, resulting in severe physical injuries. One study found that up to 50 percent of all pigs raised in a closed facility experienced severe joint damage, and 80 percent of the population had damaged cartilage. The same research revealed that the incidence of joint and cartilage damage decreased significantly once the pigs were taken out of the building and put to pasture. 12 Pigs have nowhere to flee when provoked, thus leaving the frustrated animals no choice but to fight.