Well being of animals had been historically a public concern, since the beginning of human kind history. As world's population grows there is a need for food including meat. In the last decades there has been a great improvement in poultry production based on the careful control of several aspects, among which nutrition and management (environment, health and rearing systems). Nowadays, the search for good welfare conditions is a global tendency in animal production; however issues surrounding farm animal welfare or well-being, such as definitions, measurements, interpretation, and perception, continue to be controversial. It is known that the result of a broiler not adequately housed is a direct loss in production which leads towards a thought that health, welfare and productivity are intimately connected. In the other hand hints are found in the observation of behavioral responses as well as vocalization, which may provide more precise assessment to welfare. This has been possible due to the use of information technology applied to the field of ethology as well as the multidisciplinary view of the problem. This text provides a review on broiler's welfare issues since its definition to several way of trying to assess it adequately

Poultry meat quality has been widely studied, and has become a growing demand of the international market. Parameters that affect meat quality are complex, and occur throughout the production chain. The constant concern with meat quality by the exporting sectors is a response to consumers' demands, and is achieved by increasing efficiency, and investments in personnel training on quality. Understanding where critical points are in the poultry meat production chain, and investing in solving critical problems may lead to better control and management, and consequent reduction of losses. Production and management practices, from farm to processing plant, play an important role in meat quality, and the use of technologies to reduce risk factors throughout the production chain will allow the production of better quality poultry meat not only for exports, but also for the domestic market. This review describes the main factors that influence poultry meat quality in the production chain.

Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days

This experiment was carried out in a 104 m² poultry house located between the geographical coordinates 25°45'00" south latitude and 53°03'25" west longitude and an average altitude of 550 m, from September to November, 2008. The chickens were placed in 12 pens measuring 2 m² each at a stocking density of 12 chickens m-2. This study aimed at evaluating the effect of two different initial weights (chick weight on first day of experiment) and two types of litter material on broiler production parameters, litter humidity, as well as on breast and footpad lesions. A total of 240 female Cobb® chickens, derived from the same flock of breeders, was distributed in a completely randomized experimental design with a 2 (initial weight) by 2 (litter material) factorial arrangement with three replicates per treatment. Initial weights were classified as light (34.40 - 35.22 g) or heavy (39.29 - 41.30 g), whereas wood shavings and sawdust were used as litter material. Data were analyzed by ANOVA and means were compared by Tukey's test at 95% confidence level. Initial weight significantly influenced bird performance, as chickens with heavy initial weight presented higher feed intake and body weight. Type of litter did not have any effect on breast injuries and litter humidity. However, the wood shavings litter significantly influenced footpad lesions

Brazilian poultry production is prospering, and negative-pressure broiler houses are increasingly used to improve environmental control. One important issue is the color of the side curtains used in such houses due to the influence of colors on broiler behavior. This study aimed at evaluating the influence of different curtain color on the welfare of 7-day-old broilers, considering luminosity and other environmental parameters. Chicks were housed in three different negative-pressure broiler houses either with black (T1), blue (T2), or yellow (T3) side curtains. House environment (luminosity, dry-bulb temperature, air relative humidity, air velocity, and gas emissions) and the behavior of chicks on day 7 after housing were evaluated in three consecutive flocks in the morning and in the afternoon. Data were submitted to multivariate analysis, Kruskal-Wallis' test, and Pearson's correlation test. Luminosity and ITU were influenced by curtain color, and some of the evaluated behaviors were associated with luminosity or other environmental parameter.

The objective of the present study was to characterize the scientific production regarding the factors that influence broiler chicken production, and that were published from 2000 to 2015 in journals indexed in the database of Google Scholar, Scielo, and ScienceDirect. The research was done in the Thermal Comfort Laboratory at FEAGRI-UNICAMP, and the concept of the systematic review was applied. The research criterion was initially defined (the keywords) aiming to identify and evaluate the variables that describe the experimental characteristics and the animals. The primary keywords identified were: broiler chicken from commercial strains, broiler production, rearing conditions, thermal environment, air quality, acoustic environment, light intensity, management, and heat stress. Those were the key words searched in the database of the online libraries. The selected articles were registered into an electronic spreadsheet with the title, the name of the authors, year of publication, language, the journal where it was published, the keyword, the period when the research was done, source/ database, and the abstract. A total of 167 articles were selected, and only 34 were added to the review. The use of the systematic review of the literature allowed identifying the main variables that positively influence the broiler performance, such as the temperature near the thermal comfort, the use of roof lining, besides the use of adiabatic cooling and cast bricks in the laterals. The presence of positive ventilation, as well as the use of yellow curtains and constant lighting, has also influenced a better performance to broilers.

In tropical poultry-producing countries, poultry houses usually have little environmental control. This study investigated the effect of dietary vitamin D on the incidence of leg abnormalities of a fast-growing broiler strain reared under harsh conditions. In this study, 300 one-day-old male broilers were distributed in two treatments with three replicates of 50 birds each. One group was fed a placebo and the other group was fed 25-hydroxycholecalciferol (25-OH-D3) in a soluble form. The environmental variables were weekly recorded during until birds were 49 days old. Birds were weekly gait scored, and their walking speed and vertical force while walking were assessed. Post-mortem examination was performed and skeletal lesions were assessed. Control birds presented more leg problems than those that ingested 25-OH-D3. These results suggest that dietary vitamin D is effective in decreasing the severity of lameness by reducing tibial dyschondroplasia and other leg abnormalities. INTRODUCTIONIt has been reported that the low locomotor activity of broilers coupled to their high initial growth rate of broilers results in leg problems and gait abnormalities. Long times spent sitting on wet litter may cause breast and leg skin lesions, which may contribute for the deterioration of the flock well-being (McGeown et al., 1999;Vestergaard & Sanotra, 1999;Weeks et al., 2000;Bokkers & Koene, 2004;Bessei, 2006). A causal interrelationship between the rapid growth broiler strains, low locomotor activity and leg problems has been discussed in current literature (Julian, 1998;Vestergaard & Sanotra, 1999;Kestin et al., 2001;Sanotra et al., 2001;Bokkers & Koene, 2003). However, the influence of environmental and management-related factors, such as heat stress, light intensity, age, stocking density and diet on the incidence of leg abnormalities in broiler flocks has also been reported (Edwards Jr., 2000;Edwards Jr., 2003;Dawkins et al., 2004;Bessei, 2006).The most common skeletal problems that cause leg weakness in broilers are tibial dyschondroplasia, chronic painful lameness, chondrodystrophy or angular bone deformities, valgus-varus deformities, spondylolisthesis, rickets, femoral head necrosis, curled toes, and ruptured gastrocnemius tendon (Angel, 2007). Lameness in broilers with poor gait scores significantly improved after treatment with analgesic and anti-inflammatory drugs, which has led to the assumption that the leg problems in broilers are painful (McGeown et al., 1999;Danbury et al., 2000;Weary et al., 2006;Nääs et al., 2009). Several attempts have been made to determine the broilers' locomotor deficiencies (Dawkins et al., 2004) and to increase the walking ability of the birds (Corr et al., 2007).Among the studies to reduce lameness in broilers, some are related to the use of feed additives (Rath et al., 1998)

This study compared three types of feeders for broilers: Fênix, Tube and Automatic feeders. Bird's feeding behavior and preference were considered in this the evaluation. Preference was assessed by examining birds' behavioral activities, such as eating, standing and lying around the equipments, and meal duration as function of the environmental variables. Data on the behavioral activities and meal size were collected in a broiler commercial farm using a portable video camera, and the direct footages were analyzed. The time spent in each activity, feeding bout duration and time spent near the trough were statistically analyzed using the test of means and medians. Pearson's correlation test was used to evaluate the relationship between ambient environmental data and the time of feeding. A prospective scenario was established and data were pair wised compared to it. There were interactions between environmental characteristics and feeding and lying down activities during the experiment. Eating behavior was more frequent in the area around the Tube feeder. The duration of feeding time was higher when the birds used the Tube feeder (214 ± 28s), followed by the use of the Fênix feeder (123 ± 17s) and the Automatic feeder (77 ± 29s). Birds preferred eating from the Tube feeder probably due to the absence of the partition grid above the feeder plate