Effects of Various Additives to Reused Broiler Litter on Litter Ammonia Production, Chicken Welfare and Performance

Abstract

We investigated the effects of adding alum, sodium bisulphate, bentonite, zeolite and NaturClean CSM® at 3.2, 3.2, 13, 13 and 0.9 % by weight respectively to reused litter on moisture content, pH, ammonia production, bird liveweight and conditions linked to welfare including scores for footpad dermatitis, hock burn, breast burn and breast feathering. Treatments, including no amendment, were applied to four pens each 2.25 m² with half the pens having 20% additional water added. Nineteen broiler chicks were reared in each pen up to day 42 with sampling of the litter and birds at various intervals. Litter moisture content of 31% on day 0, reduced to approximately 21% on days 7 and 14 before increasing to a value of 53% on day 42. All litter amendments except NaturClean CSM® reduced ammonia production with the greatest reductions seen with alum and sodium bisulphite on days 7 and 14. Amendments worked similarly in litter with or without water addition. There were no significant effects of litter amendment on bird weights or measures of welfare with welfare measures generally worsening with time and with initial addition of water. Ranking of reused litter treatments from 1 to 6 (best to worst) for each welfare measure, followed by the averaging of those rankings, provided mean rankings of 1.75, 2.25, 3, 3.75, 4.75 and 5.5 respectively for reused litter without amendment, bentonite, alum, sodium bisulphite, NaturClean CSM® and zeolite treatments. Both acidifying and adsorbent litter additives have potential to significantly reduce ammonia concentrations on reused litter. Further work is required to determine optimum inclusion rates and more clearly identify effects on welfare and performance.