PIG BREEDING & FARROWING TIMING GUIDE
(Commercial & Residential Farming)

OVERVIEW
Pigs are polyestrous year-round, meaning sows can cycle and conceive at
any time of year without needing specific daylight triggers (unlike
sheep or cattle). This gives farms flexibility, but there are still
strong practical reasons to time breeding around certain months.

BEST BREEDING WINDOW
- Breed: Late Fall through Winter (November - February)
- Gestation: ~114 days (3 months, 3 weeks, 3 days)
- Resulting births: March - June

WHY THIS WINDOW WORKS
- Mild spring weather is easier on newborn piglets, which are very
  sensitive to cold and drafts in their first few days of life.
- Grass and forage (for pasture-based or backyard operations) is
  coming in during spring, helping sows recover condition after
  farrowing.
- Avoids the worst summer heat. Heat stress in summer (July - August)
  is the biggest threat to pig reproduction:
    - Reduces conception rates
    - Reduces litter size
    - Can cause early embryonic loss
    - Lowers boar fertility

WHY SUMMER BREEDING IS AVOIDED
Breeding in summer (aiming for fall litters) hits reproduction during
peak heat stress, lowering success rates -- even though the resulting
fall farrowing season has fine weather.

COMMERCIAL vs. RESIDENTIAL OPERATIONS
- Commercial (indoor, climate-controlled): Often breed year-round on
  a rolling schedule since barns buffer temperature extremes. The
  priority is consistent output, not season.
- Residential / small-scale / pasture-based: Benefit much more from
  timing births for spring, since piglets are exposed to real weather
  and predators, and forage availability matters more.

NOTE
Ideal timing shifts depending on breed and local climate (e.g. hot
southern climates vs. cold northern climates).
