Here we present a newly developed tool for continuous recordings and analysis of novelty-induced and baseline behaviour of mice in a home cage-like environment. Aim of this study was to demonstrate the strength of this method by characterizing four inbred strains of mice, C57BL/6, DBA/2, C3H and 129S2/Sv, on locomotor activity. Strains differed in circadian rhythmicity, novelty-induced activity and the time-course of specific behavioural elements. For instance, C57BL/6 and DBA/2 mice showed a much faster decrease in activity over time than C3H and 129S2/Sv mice. Principal component analysis revealed two major factors within locomotor activity, which were defined as 'level of activity' and 'velocity/stops'. These factors were able to distinguish strains. Interestingly, mice that displayed high levels of activity in the initial phase of the home cage test were also highly active during an open-field test. Velocity and the number of stops during movement correlated positively with anxiety-related behaviour in the elevated plus maze. The use of an automated home cage observation system yields temporal changes in elements of locomotor activity with an advanced level of spatial resolution. Moreover, it avoids the confounding influence of human intervention and saves time-consuming human observations.

Breakout analysis of 11,254 chicken eggs that failed to hatch was used to assess the influence of storage days on the distribution for time of embryonic mortality during incubation and on reproductive efficiency. Eggs were collected over 30 d, stored from 2 through 18 d, and incubated in two hatches. For each storage day within hatch, proportions of embryonic mortality during each of the 21 d of incubation, among embryos that did not survive incubation, were fitted by a diphasic Weibull distribution. Multivariate analysis was used to assess the influence of hatch and storage days within hatch on parameters of the distribution and on two measures of reproductive efficiency, proportions of embryonic mortality during incubation among all eggs incubated P(mort) and among fertile eggs incubated P(mort/fert), and to obtain partial correlation coefficients. Storage days influenced the distribution for time of embryonic mortality in each hatch, but the effect was different for each hatch. As the number of storage days increased, P(mort) and P(mort/fert) increased. Partial correlations showed that P(mort) and P(mort/fert) decreased as the proportion of embryos that died during the first phase decreased and as duration of the second phase increased. The shape of the distribution for time of mortality during incubation influenced reproductive efficiency. Factors that influence the shape of this distribution, other than hatch and storage days within hatch, should be studied to increase reproductive efficiency in the poultry industry.

Pigs are non-specialist feeders with high capacities to adapt their diets within wide limits to prevailing and unpredictable conditions. Under husbandry conditions however, pigs are usually fed under extremely predictable conditions, i.e. with highly uniform and standardized diets, ad libitum or at standardized times. Although pigs, in this way, obtain their food with the lowest amount of effort and costs, studies in various different species have shown that animals may prefer to work for food, rather than receiving food for free. In addition, recent studies showed that animals may also be sensitive to risk and variance associated with food sources which may be expressed as a preference for unpredictable over predictable schedules when working for food in an operant task (risk-sensitive foraging). Since feeding is an important aspect of the daily animal husbandry routine which is likely to have a high impact on animal welfare, it is important to know whether (domesticated) pigs also prefer to work for unpredictable as opposed to predictable feeding schedules under husbandry conditions. For that purpose, nine gilts (Finish Landrace  York) were trained to respond in a two-choice operant task. In Test 1, pigs could choose between response options associated with either a FI-8 s schedule (predictable delay) or a VI-8 s reinforcement schedule (unpredictable delay). In Test 2 they could choose between choice options associated with the delivery of either a predictable food item (identical at all times) or an unpredictable food item (differing in nature across trials), delivered according to a FI-8 s schedule. Based upon natural foraging strategies of pigs it was expected that that pigs would prefer the unpredictable options in each test. However, the results from our experiment did not support this hypothesis. Factors that may influence the pig's sensitivity to variability in food rewards, are discussed. #

Proper assessment of factors contributing to failure of an egg to hatch, i.e., infertility and embryonic mortality, is important in poultry production. A model consisting of the sum of two cumulative logistic distributions was proposed previously to describe the distribution for time of mortality during incubation; model parameters, including probabilities of infertility and mortality, were estimated by the method of least squares. The objective of this paper was to improve the previous model and method of estimation by evaluating alternative distributions and methods; we propose four recommendations. First, probabilities of infertility and mortality should be estimated as observed proportions rather than as model parameters. Second, parameters of the distribution for time of mortality should be estimated using a diphasic Weibull distribution rather than a diphasic logistic distribution. Third, parameters of the distribution for time of mortality should be estimated using noncumulative proportions rather than cumulative proportions. Fourth, parameters of the distribution for time of mortality should be estimated by maximum likelihood rather than by least squares. The minimum Hellinger distance, however, is a good alternative to maximum likelihood to estimate distribution parameters if the distribution of mortality is not known exactly or if the data contain outliers.