2001. Effects of altering growth curve and age at photo-stimulation in female broiler breeders. 2. Egg production parameters. Can. J. Anim. Sci. 81: 477-486. An experiment was conducted to evaluate the effect of differences in growth curve and age at photostimulation on egg production parameters and carcass traits at 61 wk of age in broiler breeder hens. Pullets were grown on one of three growth curves: STD (standard), LOW (150 g lighter than STD) and HIGH (150 g heavier than STD), and photostimulated at either 19 wk of age (19WK) or 21 wk of age (21WK). The egg production and BW of 36 birds per interaction were individually monitored from photostimulation to 61 wk of age. Individual, daily egg production records were analyzed for total, settable, and defective egg production, rate of production, sequence length, and egg weight. Eggs were incubated for determination of fertility, hatchability, and embryonic mortality parameters. All birds remaining at 61 wk of age were processed for determination of carcass and reproductive morphology. Unless otherwise stated, all significance was assessed at the P < 0.05 level. Earlier photostimulation age advanced age at sexual maturity, but reduced the first egg weight. Weight of the first egg did not differ among growth curves. Settable egg production to 61 wk was not affected by growth curve, with settable egg production ranging from 157.5 eggs in STD birds to 164.1 eggs in HIGH birds. The HIGH birds produced more double-yolked eggs than LOW birds. Photostimulation age did not affect egg production. Eggs of the LOW birds underwent more embryonic loss during 1 to 7 d of incubation than either STD or HIGH eggs. At 61 wk of age, the shank length of birds on the LOW profile was less than that of the STD birds or the HIGH birds. Abdominal fatpad as a percentage of BW differed among growth curve treatments, comprising 4.46% (LOW), 5.06% (STD), and 5.69% (HIGH) of hen BW. Ovary weight of HIGH birds (44.7 g) was higher than that of LOW (39.2 g) or STD birds (37.7 g), but contained a similar number of large yellow follicles. The proportion of large yellow follicles in multiple follicle sets at 61 wk was correlated with unsettable egg number (r = 0.265), and was negatively associated with chick number (r =-0.269). There was no production advantage to early photostimulation, and egg and chick production were not negatively affected by a moderate raising or lowering of the growth curve.. 2001. Modification de la courbe de croissance et de l'âge à la photostimulation et leur incidence sur les pondeuses de poulets de chair : 2. Paramètres de ponte. Can. J. Anim. Sci. 81: 477-486. Les auteurs ont effectué une expérience pour déterminer quels effets une modification de la courbe de croissance et de l'âge à la photostimulation aurait sur les paramètres de ponte et la conformation de la carcasse des pondeuses d'oeufs d'incubation âgées de 61 semaines. Les poulettes ont été réparties en trois groupes de courbe de croissance différente-soit STD (standard), FAIBLE (150 g de moins que STD) et ÉL...