37 37 LOHMANN TIERZUCHT › MANAGEMENT GUIDE Rearing Starter / Pre-starter phase Growing phase Developer phase Stocking density, housing condition, temperature variation and feather cover in combination with a higher energy demand due to the bird’s movement, all have a bearing on the nutritional demands of the pullet. It is a fact that management within these systems plays a bigger role than in conventional production sys- tems. Therefore, the nutrient supply must be adjusted accordingly in order to achieve the correct body weight development (weight and condition), uniformity and feed intake capacity. Monitoring the pullet’s body weight, from day old to at least week 32, is advisable to facilitate nutritional and management decisions accord- ing to each phase. Day old till week 5 is a critical pe- riod where the development of the main organs, bone and immune sys- tem take place. It’s very important to achieve and maintain the target body weight during this period. Any reduction in nutrient and feed intake at this time will have a pronounced negative effect on persistence and mortality later in production. The starter/pre-starter diet should in- clude a relatively high energy density (>_ 2850kcal / kg; 11,90 MJ / kg). Dur- ing this period, the protein/amino acid levels are relatively high due to their strong influence on early skele- tal development and growth (Leeson & Summers, 1989). Regarding feed format, micro-pellets (0 –2 weeks) or crumbs (0 –4 weeks) can be an option to enhance a good start to the flock, as it can encourage feed intake and ensure that all pul- lets have access to same nutrients. However, it is always recommended to feed a homogenous mash feed. Between weeks 5 and 10, the empha- sis is now on bone and muscle devel- opment as we head towards the full development of the skeletal frame. Therefore, it is critical to achieve the correct body weight according to our production target. Changing from the starter diet should only be considered when the body weight target is achieved. Recommendations for Nutrient Levels for LOHMANN Pullets From week 10 till week 16, the nutri- ent density may be reduced due to a lower nutrient demand. During this period, gastrointestinal tract and feed intake capacity development takes place. It is essential to develop this capac- ity early to prepare for the onset of lay when the demand for nutrients is diverted to egg production alongside continued growth. Pullet and layer nutrition is a con- tinuous process ensuring diets meet all nutritional requirements. Feeding pullets and hens in alterna- tive systems is not only related with supplying feed nutrients but is also a compromise between feed format and presentation, feed management and equipment, stocking density and feeding space, light programs and light intensity plus environmental conditions. The interaction between these factors plus the cost of ingre- dients, should be considered in the decision-making process when look- ing at the nutrient density for each phase of the feeding programs. From a nutritional point of view, the main difference in alternative pro- duction is a higher energy require- ment due to increased movement. Feeding & Nutrition LOHMANN TOOLBOX