They should be weaned when about three weeks old and placed in separate pens, separating the young males from the females. It is then well to let the mother rest two or three weeks before being placed in the breeding pen again.
It is best to let each female have not over four litters a year. The young ones are apt to be stronger and there will be more of them in a litter. You will get about as many of them per year with four litters as with five and have better stock. Some breeders, especially for show stock, get only three litters a year.
When your young females are about four months old, they should be placed in the breeding pen. Best results and surer are obtained by keeping one male with four or five females and letting them stay together until you are sure each female is bred. They begin to show that they are with young in about 30 days or sooner and get to be very large before giving birth.
It is best to have several females with young together in the same pen, as they will nurse each other’s young indiscriminately and the little fellows seem to know no difference. While the males do not kill the little ones, still they should never be left in the pen with nursing mothers, as they will bother them.
Many breeders do not have special breeding pens, but keep all of the females together and put males in with them. This is hardly the best plan, however. The females must not be allowed to litter in the big pen, but always in special pens or hutches.
It is best to have different breeding pens or hutches, so you can get young stock that is unrelated. You will have many chances to sell breeding stock and it does not do to supply males and females that are full brother and sister. By using care you can so breed your stock that you can keep different batches of them that are not very closely related.
Line Breeding.
By line breeding, we mean breeding the same stock without getting new males. It is the method used by breeders of fancy stock to get any special color or marking. It is not inbreeding in the true sense of the word.
In line breeding you breed the father to his daughter and the son to his mother. This arrangement is all right and gets splendid results. You must avoid, however, breeding full brothers and sisters. It is also well to breed pigs that are similar in color and marking. For instance: Breed whites with whites and blacks with blacks, etc. By line breeding you can get almost any color you want. If you wanted to get solid red, say, out of a mixed lot, you should breed your reddest male to your reddest female. Then breed the father to his reddest daughter and the reddest son to his mother. Continue in this way and eventually you will get solid reds.
For commercial purposes, however, we think it is best to get new males every now and then. If you have only one male at the start, you should get a new one when the young ones of your first litter are old enough to breed. This will permit you to get stock not closely related and that you can sell for breeding and pet purposes.