The aim of the experiment was to study the effect on litter performance of two oral supplementation strategies on piglets born weighing 1.35 kg or less (SP; CON: no oral supplementation; COL: supplementation with 15 mL of sow colostrum orally administered to piglets within 4 h after the farrowing was completed). Two levels of cross-fostering strategies, performed 24 h after farrowing, were also studied (HL: litters fixed at 12 piglets, ensuring that less than 50% of the piglets of the litter were SP; LL: litters fixed at 12 piglets, with most of the piglets of the litter being SP; in both cases the aim was to minimize moving piglets from one sow to another as much as possible). The combination of the 2 management strategies described above resulted in a 2 × 2 factorial model. Forty-six litters were used. Litters were allocated to 1 of the 4 treatments: CON-HL, CON-LL, COL-HL, and COL-LL. Piglets were weighed on d 1 and 19 postpartum. Mortality was recorded. On d 4 postpartum, a 2-mL blood sample was obtained from 79 SP piglets born from multiparous sows included in the experiment. To obtain a negative control group, blood samples were obtained on d 4 postpartum from 8 additional SP piglets that were separated from their mothers at birth and bottle fed with milk replacement for 12 h. LL sows had lower within-litter CV of BW at d 1 than HL sows (16.2% vs. 21.9% ± 0.91%; P = 0.003), but they did not differ for litter CV of BW at d 19 (23.2% vs. 23.4% ± 1.72%). At d 19, HL sows had fewer dead piglets per litter than LL sows (0.80 vs. 1.69 ± 0.307; P = 0.022), and COL-HL sows had fewer dead piglets per litter than CON-HL (0.47 vs. 1.14 ± 0.160; P = 0.062). Cross-fostering SP in the same litter did not prevent a litter's CV of BW from increasing at weaning. Piglets from the COL group had higher IgG concentration than piglets from the CON group (P = 0.001). However, piglets from the negative control group had lower IgG concentration than those from the COL and CON groups (5.41 ± 2.320 vs. 30.60 ± 1.582 and 21.53 ± 0.951 mg/mL, respectively; P < 0.001 in both cases). Allocating small piglets to the same litter through cross-fostering had a negative effect on mortality and did not improve litter CV of BW at weaning. Colostrum supplementation of SP piglets improved IgG blood level on d 4. In addition, in nonhomogenized litters, colostrum supplementation of SP piglets might be a good management strategy to improve litter performance.