Sequential feeding with variations in energy and protein levels improves gait score in meat-type chickens.

Feeding broilers by alternating different diets for 1 or 2 days is known as sequential feeding, and it possibly reduces leg problems since it slows down early growth and may enhance general activity. The present study compared continuous feeding with a standard diet (C: metabolisable energy = 12.55 MJ/kg, crude protein = 190 g/kg) with alternations of a high-energy/low-protein diet (E+P-:+7% ME; -20% CP) and a low-energy/high-protein diet (E-P+: -7% ME,+20% CP) and investigated its effects on growth, behaviour and gait score in 352 male Ross broiler chickens. Sequential feeding was carried out during ten 48-h sequential-feeding cycles from 8 to 28 days of age. Three treatments were compared: complete diet (C) and two alternations of diets varying in protein and energy contents (S1: E+P- followed by E-P+; and S2: E-P+ followed by E+P-). Chickens received the same feed during the starter and finisher periods (0 to 7 and 29 to 38 days of age). Body weight (BW), feed intake, general activity and gait score, bone quality and carcass conformation were measured to evaluate leg condition and general performance. Sequential feeding significantly reduced BW at 28 days of age (S1: -9.1%; S2: -3.7%/C group; P < 0.05) and S1 were lighter than S2. In both sequential groups, time spent standing increased (C: 28%; S1:33%; S2: 35%; P < 0.05) and leg abnormalities decreased (mean gait score: C: 2.61; S1: 2.45; S2: 2.38; P < 0.02). This improvement was not related to changes in bone quality. BW at slaughter was impaired in Group S1 only, and the feed conversion ratio throughout the rearing period was not significantly impaired by sequential feeding. However, abdominal fat was higher in the S2 group. Sequential feeding using diets varying in energy and crude protein can be a useful method of reducing leg problems in broilers since it improves gait score without impairing growth performance when used as early as 8 days of age and up to not less than 8 days before slaughter in order to compensate for reduced growth. This improvement can be explained by reduced early growth and enhanced motor activity. However, it appears that the low-energy diet should be given first in order to avoid a reduction in BW at slaughter.

Influence of increased environmental complexity on leg condition, performance, and level of fearfulness in broilers.

We hypothesized that increased distance between resources and stimulation of foraging behavior, through altering the degree of environmental complexity by using moving lights and scattering whole wheat in the litter, would improve physical activity of broiler chickens. Increased activity may potentially improve leg condition and performance and decrease the level of fearfulness in broilers. To test this hypothesis, 1,800 1-d-old male broilers were divided into 40 groups of 45 birds each (10 birds/m2). Each group was assigned to one of four treatments (10 replicates) as follows: barrier treatment (B) contained three barriers placed between the drinker line and the feeder. The light treatment (L) consisted of brightly colored moving lights projected on the pen floor for four 1-h periods/d throughout rearing. For the wheat treatment (W) wheat was dispersed on the floor from Days 8 to 17. Control birds (C) were maintained under standard management. Body weights and consumption were obtained throughout the rearing period. Gait score (GS), tibia length and diameter, fluctuating asymmetry (FA), bone ash, tibial dyschondroplasia (TD), bone breaking strength, and tonic immobility (TI) were measured at slaughter age. Mortality, body weight, feed conversion, FA, bone ash, TD, bone breaking strength, and TI duration did not differ significantly among groups. L birds had a higher GS than C and B birds and W birds had a higher GS than C birds (P < 0.05). Provision of barriers significantly increased the diameter of the tibia diaphysis (P = 0.05), which is a promising result for further studies to improve leg condition.

Typology of activity bouts and effect of fearfulness on behaviour in meat-type chickens.

Increased physical exercise is known to prevent leg problems in meat-type chickens. Our aims were to study in detail the organisation of general and locomotor activity, to determine how physical exercise could be promoted and to investigate the effects of tonic immobility (TI) duration on spontaneous activity. Chicks were allocated to two groups according to their TI duration at 3 and 20 days (fearful birds, HF, n=11; non-fearful birds, LF, n=14). The behaviour patterns expressed by awake birds were recorded as 'activity bouts'. Activity bouts were then classified into five classes according to the most long-lasting activity in the bout. The behaviour patterns were similar in both groups. The FORAGING class contained long-lasting bouts with high levels of locomotor activity which decreased considerably with age, when bouts of EATING and DRINKING classes became more and more numerous. Bouts in the PREENING and NONE classes contained low activity. In conclusion, the level of activity in home pens was poorly related to TI. Categorisation of bouts into five classes is valuable to understand the general organisation of activity in chickens. The FORAGING class included bouts with high levels of locomotion and it could thus be used as a general indicator of activity.

Sequential feeding can increase activity and improve gait score in meat-type chickens.

This study investigated the short- and long-term effects of sequential feeding by alternating low-and high-lysine diets during the day on growth, gait score (GS), and behavior in broilers. From Days 2 to 12, 6 pens of 10 birds were assigned to control treatment and fed a standard normal lysine diet (NL) (ME = 3,250 kcal/kg, CP = 23%, Lys = 1.19%) and six pens of 10 birds were assigned to the sequential treatment and fed a low-lysine diet (LL) (Lys = 0.85%) for half of the day and NL for the other half of the day. From Days 13 to 21, all groups were fed NL, and from Days 21 to 42, they were fed a grower diet. Sequential (S) chicks were lighter than Control chicks at Days 13 (304 +/- 6 vs. 378 +/- 7 g) and 42 (2,588 +/- 31 vs. 2,714 +/- 10 g) and had better leg condition at Day 42 (mean GS = 1.6 +/- 0.1 vs. 2.1 +/- 0.1, P < or = 0.05). During a day of S feeding, S birds ate less and wasted more LL than NL. Sequential birds spent less time standing and more time lying idle when fed LL than when fed NL. Sequential birds spent more time eating than Control birds, and they gradually increased the number of pecks in the litter during a sequential feeding day. The results suggest a major effect of food composition on behavior. Sequential feeding could be a means of decreasing leg problems in broilers.

Early locomotor behaviour in genetic stocks of chickens with different growth rates.

Reduction in exercise increases the occurrence of lameness in meat-type chickens. Locomotor activity is dramatically reduced during the finishing period in chickens from fast-growing genetic types compared to slow-growing genetic types, but it is not known whether this difference is already present during the starting period and may be influenced by genetic factors. In order to define the effect of genetic origin on early locomotor behaviour, exercise was compared from 1 to 22 days of age in two meat-type chicken stocks differing in growth rate: male broilers (B) which grow fast and are often lame, and male "label rouge" chickens (L) which grow slowly and are rarely lame.Time budget (lying, standing, drinking, eating, walking) was measured by scanning in six repetitions of five birds (density=2.5 birds/m(2)) at 1, 8, 15 and 17 days of age. Standing bouts were analysed by focal sampling at 2-3, 6-7, 13-14 and 20-21 days of age.B chicks spent less time standing than L chicks at 15 days of age (B=13+/-2%, L=24+/-1%, P<0.01) and 17 days of age, and spent more time lying at 17 days of age (B=73+/-3%, L=60+/-4%, P<0.05).The major part (74%) of the total active time observed by focal sampling was linked to feeding activity. At 2 and 3 days, the activity of B chicks was half that of L chicks during standing bouts (duration of walking per bout: 19+/-4 s for B; 45+/-4 s for L, P<0.05). The activity observed by focal sampling during non-feeding bouts at 20-21 days was significantly correlated with the corresponding data recorded at 2-3 days in the same chicks in the B stock but not in the L stock.We concluded that (1) both B and L genetic stocks have the same overall activity during the first 3 days of age (scanning) but they exhibit different organisation and composition of standing bouts (focal sampling). (2) Genetic factors are probably involved in the expression of locomotor behaviour in very young chicks. (3) The correlations between the levels of activity at early and later ages suggest that selection of young mobile broiler chicks might increase activity at a later age and might therefore reduce the occurrence of leg abnormalities.