The research was carried out to determine the relationship between kids birth weight and placental characteristics of hair goats grown in poor condition during the critical period of pregnancy. Particularly, it was aimed to investigate the placental relation of high mortality rate especially in twin kids. Placentas were collected from 52 goats at normal kidding. There were 36 singleton and 16 twin pregnancies and 42 female and 26 male kids. During the mating period (September), the goats grazed on poor pasture for 12 hours and nothing was added to the pasture. The date of mating was recorded and goats were fed indoor after the 60th day of pregnancy. During the time they were inside, 200 g/day barley, ad libitum the hay and water were given. Kids were weighed and sexed at 12-24 h after birth. Placentas were collected immediately and brought to laboratory and placentas were carefully disturbed water and weighed. Each placenta was opened with a scalpel and the cotyledons were separated from chorioallantois and counted. The effects of birth type, sex, parity and vitality on placental and cotyledon traits were analyzed by the general linear model procedure in SPSS using a completely randomized design. When the birth weight was 2.83 +/-.07 in live kids, it was 1.31 +/-.23 in dead kids and this difference was statistically very significant (p<0.001). In addition, placental efficiency was affected by the vitality of kids (p<0.05) and we observed that there was no x large cotyledon (>51 mm diameter) in the dead kids. The low placental and cotyledon characteristics of kids who died before weaning showed that placental and cotyledon traits have an effect on kids' vitality. The result showed that there were significant differences (p<0.05) among parity for placental weight and cotyledon density. Birth type affected placental weight (p<0.001), cotyledon density (P<0.01) and average cotyledon surface area (ACSA) (p<0.05). Large cotyledon number, cotyledon length and cotyledon width were affected (P<0.01) by birth type. It was observed that there is a direct correlation between ACSA and cotyledon length (r=0.985; p<0.01), cotyledon width (r=0.969; p<0.01). However, a negative correlation between ACSA and small cotyledon number (0.553; p<0.01), cotyledon density (-0.779; p<0.01) is determined for hair goats. As a result, we suggest that cotyledon efficiency is a much more precise and reliable measure of placenta functional ability. These data have shown that manipulation of the prenatal period can affect birth weight, newborn losses, average daily live weight gain, market weight, health and meat production economy and profitability in the livestock industry.