This may be of interest.
1.There are more piglets born dead among multiple farrowing, usually the fifth or the last three piglets. This is perhaps because of the length of the womb and the umbilical cord. For about one meter of the cord to be borne by the piglet, (while it is normally only 70 cm. long) in its length of passage, the cord is stretched and cut and so the last piglets lose breath before they are able to emerge.
2.It could also be due to the aging mother, (which may have farrowed five or six times). Usually, delivering dead piglets start from the fourth to the seventh farrowing. The next farrowing can be seen in the piglets that have been delivered.
3.Other causes could be the stress borne by the mother pig before delivery -perhaps she has had a fight or had undergone much difficulty in the last weeks before delivery.
4.Fat mother pig have difficulty in delivery.
5.If the mother is anemic or lacks Vitamin E, the piglet cannot survive its delivery because it also lacks Vitamin E.
6.Death of the piglet could also be due to the mother pig’s lack of Vitamin A in her diet, months before delivery.
7.If the mother pig’s meal becomes contaminated with molds, it will deliver weak or dead piglets.
8.If at a certain time several mother pigs deliver dead piglets, infections or sickness could be the cause. There are diseases for instance that are transferrable from cats to pigs, but seldom vice versa. If the mother pig gets contaminated while the piglet is still in its womb, this could result in abortion. But if the infection comes about at the latter part of the pregnancy, the piglet will be born dead.
9.If the pig pen lacks proper ventilation, and much more when there is a gas leak around, or if the carbon monoxide level (from vehicle exhausts) is high, this could result in the death of the piglet in the pig’s womb.