Three experiments were performed to determine the effect of feeding time on shell quality and oviposition time in broiler breeders. Mean eggshell thickness was increased significantly by 3.5 microm (approximately 1%) per h delay in feeding time when hens were housed in individual cages. However, eggshell thickness was not significantly affected by feeding time when birds were housed on litter floors. Mean oviposition time was delayed relative to lights on by 5 min per h delay in feeding time. Egg weight was not significantly affected by feeding time, suggesting that differences in shell thickness and oviposition times were not due to increased oviducal transit times. Producers who wish to implement delayed feeding may have to turn lights on earlier than usual to compensate for delayed oviposition times.

1. Oviposition times were recorded for broiler breeder hens under 8-, 10-, 11-, 12-, 13-, 14- and 16-h photoperiods. 2. Mean oviposition time (MOT) was delayed relative to dawn by approximately 0.5 h for each 1-h increase in photoperiod up to 14 h, but was similar for 14- and 16-h photoperiods. However, the 0.5 h/h regression for the time when half the eggs were laid continued through to 16 h. 3. The rate of change in MOT for each 1-h increase in < or = 14-h photoperiod was similar to that reported for early and modern egg-type hybrids, but, compared with modern genotypes, time of lay itself was 1 h later than white-egg and 2.5 h later than brown-egg hybrids. 4. At photoperiods < or = 12.25 h, the number of eggs laid before dawn increased by 4-5% for each 1-h reduction in daylength.

1. Broiler breeder pullets were maintained on 10-, 11-, 12-, 13-, 14- or 16-h photoperiods to determine the effect of constant photoperiods on sexual development in broiler breeders. The birds were fed to achieve a 2100 g body weight at approximately 17 or 20 weeks to see if the photosexual response was modified by rate of growth. 2. In both body weight groups, pullets maintained on 10h were the first to reach sexual maturity (50 eggs/100 bird-d), and these and the 11-h pullets matured significantly earlier than any of the other photoperiod groups. Pullets maintained on 13 or 14 h matured latest, at about 3 weeks after the 10-h pullets, though both were only marginally later than the 12- or 16-h birds. These differences in maturation probably reflect the different rates at which photorefractoriness is dissipated in broiler breeders reared on photoperiods that vary in their degree of stimulatory competence. 3. There were no significant interactions among the photoperiods and the ages at 2100 g; faster-growing birds consistently matured about 10 d earlier than conventionally grown pullets.

1. In two trials, broiler breeders were grown to a mean body weight of 2.0 to 2.2 kg at 20 weeks on 8L:16D and transferred to 16L:8D at various ages between 69 and 175 d of age at mean body weights varying between 1.0 and 2.7 kg. Other groups were grown to have a mean 20-week body weight 0.87, 1.15, 1.25 or 1.37 of the normal birds and photostimulated simultaneously with the normal weight birds. Controls were held on 8L:16D in each weight group. In a third trial, broiler breeders were transferred from 8L:16D to 16L:8D at 45 (ad libitum fed), 75 or 90 d (mild feed control), when the mean body weight of each group had reached 2.1 kg. Controls weighing 2.0 kg at 20 weeks were held on 8L:16D or 16L:8D. 2. In trial 1, photostimulating normal weight birds at 69, 76, 83 or 97 d delayed maturity and widened the spread of individual maturities, whilst transferring to 16L:8D at 111 or 125 d advanced maturity. Increasing the mean 20-week body weight to 2.8 kg advanced maturity in birds transferred to 16L:8D at 97, 111 or 125 d. Birds photostimulated at 69, 76 and 83 d matured at a similar age to controls held on 8L:16D. 3. In trial 2, transferring normal weight birds to 16L:8D at 91, 112, 133, 147, 161 or 175 d advanced maturity. Reducing the 20-week mean body weight to 1.91 kg delayed maturity in birds photostimulated at 91 or 112 d, but advanced it in birds photostimulated at 112, 133, 147, 161 or 175 d. Sexual maturity was similar for birds with a 20-week mean body weight of 2.54 or 2.74 kg, with advances for all groups photostimulated between 91 and 175 d. 4. In trial 3, birds maintained on 16L:8D matured later than birds held on 8L:16D, but maturity was advanced when birds were transferred to 16L:8D at 45, 75 or 90 d at a common body weight of 2.1 kg.

Feeding time has the potential to influence the performance of adult broiler breeder flocks and is thus of great importance. A literature review is presented concerning the responses of adult broiler breeders to feeding time.It appears that there is no benefit in feeding broiler breeders later in the day with regard to egg numbers or egg weight. There is a potential improvement in shell quality that results from feeding later in the day or from splitting the daily feed allocation across more frequent feeding periods throughout the day. However, anticipated improvements in shell quality due to delayed feeding times may not be realised, particularly when birds are housed on litter floors. Furthermore, improvements in shell quality may not be translated into improvements in hatchability due to increases in shell thickness adversely affecting the water vapour conductance of the eggshell. Broiler hatching egg producers should be aware that later feeding times may delay the time of oviposition, which may demand changes in farm procedures. Furthermore, delayed feeding times may result in feeding activity coinciding with other important periods of activity, such as mating and oviposition, resulting in a reduction in fertility and an increase in the production of eggs with abnormal shells. The current commercial practice of feeding adult broiler breeders early in the day, at, or near, lights-on, is justified, as feeding at this time has positive consequences for other aspects of hatching egg production. However, afternoon feeding is not necessarily detrimental and may be an option to consider in cases where improvements in shell quality are required, although this may not be the solution for hatchability problems. If a change in feeding time is under consideration, environmental conditions, particularly the photoperiod and ambient temperature, must be taken into account, and any changes should be made gradually, as broiler breeders may be sensitive to abrupt changes in feeding time. Furthermore, changes in the feeding schedule should be accompanied by close monitoring of performance parameters, including the number of settable, abnormal and floor eggs, percentage of fertile eggs, and hatch of fertiles. BRILLARD, J.P., GALUT, O. and NYS, Y. (1987) Possible causes of subfertility in hens following insemination near the time of oviposition. British Poultry Science 28: 307-318. CAVE, N.A. (1981) Effect of diurnal programs of nutrient intake on the performance of broiler breeder hens. Poultry Science 60: 1287-1292. CRAIG, J.V. and BHAGWAT, A.L. (1974) Agonistic and mating behaviour of adult chickens modified by social and physical environments. Applied Animal Ethology 1: 57-65. DANIEL, M. and BALNAVE, D. (1981) Responses of cross-bred layers fed at specific meal times. British Poultry Science 22: 347-354. Interrelationships between diet and elevated temperatures (cyclic and constant) on egg production and shell quality. Poultry Science 56: 1178-1188. DE AVILA, V.S., PENZ JR., A.M., DE BRUM, P.A.R., ROSA, P.S., GUIDONI, A.L. an...