Bloody Droppings in a Broiler House: Treat and Hold, or Sell Now?
Mr Phiri placed 1,200 broiler chicks in one house. On day 26 he finds 8 dead birds in 24 hours (normally 2 to 3), feed intake down 15%, wet caked litter under the drinkers, and birds huddled with ruffled feathers. Fresh droppings on the litter are streaked with blood. Average live weight is 1.3 kg. The nearest laboratory is three days away, and a neighbouring farm confirmed coccidiosis last week. His veterinarian can supply a sulphonamide coccidiostat as a three-day water treatment, with a 10-day withdrawal period before slaughter. Feed costs $0.55/kg and birds eat about 0.12 kg/day; overheads are $0.03 per bird per day; live broilers sell at $2.20/kg; healthy birds should reach 2.2 kg by day 39. He asks whether to sell the flock now or treat and hold.
1. Use his figures to compare selling the flock now with treating and selling at day 39. Show the arithmetic and give a recommendation.
Read the worked answer
Sell now. Birds left = 1,200 − 8 = 1,192. Revenue = 1,192 × 1.3 kg × $2.20 = $3,409. No further feed or overhead costs are incurred.
Treat and hold. Treatment runs days 26 to 28, so a 10-day withdrawal pushes the earliest sale to day 39, which happens to be the day the birds should reach 2.2 kg. Assume good control and about 1,180 survivors sold (average 1,185 in the house over the period). Revenue = 1,180 × 2.2 × $2.20 = $5,711. Extra feed = 1,185 × 0.12 kg × 13 days = 1,849 kg × $0.55 = $1,017. Extra overheads = 1,185 × $0.03 × 13 = $462. Drug cost, say $60. Net from the hold = 5,711 − 1,017 − 462 − 60 = $4,172.
Comparison. $4,172 − $3,409 = about $763 extra by treating and holding.
Recommendation. Treat and hold, but only because the margin is real and the withdrawal date coincides with the target weight. The decision changes if mortality does not fall within 48 hours: at 3% daily loss the arithmetic turns negative quickly, so count dead birds twice a day and set a trigger point for emergency slaughter.
2. What must he do about the withdrawal period and records, and which one management change would most reduce the risk next cycle?
Read the worked answer
Withdrawal and records.
- Write the drug name, batch, dose, dates of treatment (days 26 to 28) and the calculated earliest sale date (day 39) in the house record sheet and on the house door before treatment starts.
- Do not sell, and do not allow a buyer to collect birds, before day 39, whatever the price offered. Residues in meat can lead to condemnation, loss of the buyer and legal penalties, and the whole $763 margin depends on compliance.
- Keep the vet's prescription and any drug container labels filed with the flock record, and record mortality and feed use daily so the effect of treatment can be assessed.
The management change that matters most: litter and drinker management. Caked litter under the drinkers is where the oocysts survive and sporulate. Raising the drinkers to shoulder height, repairing leaks, adding dry bedding and increasing ventilation to keep litter friable attacks the parasite where it multiplies. Alongside this, plan the next cycle deliberately: use a coccidiostat in the feed or a vaccination programme, and never let the same litter be reused without complete removal and disinfection.
Treating the birds without fixing the litter simply buys time; the next flock with wet litter and a high oocyst load will break down the same way.