Elevated Platform Research Articles

An attempt to use sound-imprinting to attract broilers onto elevated platforms for night-time roosting

Welfare of fast growing broilers is often compromised due to leg health issues. A more complex environment such as the provision of elevated platforms facilitates activity and improves leg health in fast growing broilers. Thus, encouraging the use of elevated platforms might further enhance leg health. Chickens are known to follow the mother to the elevated platforms to roost, and if the mother is not in the vicinity the chicks will follow her vocalisations. This study aimed to investigate, whether exposing broiler chickens to a sound before and/or after hatching could be used to manipulate chickens to move onto elevated platforms for roosting. We further aimed to identify the effects of such sound-imprinting on chickens’ leg health. A 2 by 2 factorial design was used, and the chicks were either imprinted on white noise before and/or after hatching or were not imprinted. After seven days of treatment post hatching, speakers installed above the elevated platform played the same recording as used for the sound exposure for 10 min each day. Thereafter, barn lights were turned off for four hours. The sound from above the elevated platform was played to imprinted and non-imprinted chickens. Starting at eight days of age, we weekly recorded the number of birds on the elevated platform before the playback, all changes in position between floor and elevated platform from before to after the playback, and all changes in movements either to or away from the playback source (i.e. speaker) after 10 s of recordings. Furthermore, we assessed gait score weekly and pododermatitis score and breast blisters at slaughter at 42 days of age. Data were analysed with Generalized Linear Mixed Models. Our results show that imprinting (or our attempts thereof) had no effect on the use of elevated platforms as well as on any health score. Additional research needs to identify, if auditory imprinting could be strengthened using visual cues in the sensitive post-hatching period, or if another more natural sound (e.g. a recording of a broody hen) can elicit a stronger imprinting effect.

Performance Analysis of Hybrid UAV Networks for Probabilistic Content Caching

Caching content in small-cell networks can reduce the traffic congestion in backhaul. In this article, we develop a hybrid caching network comprising of unmanned aerial vehicles (UAVs) and ground small-cell base stations (SBSs), where UAVs are preferred because of their flexibility and elevated platform for line of sight. First, we derive the association probability for the ground user affiliated with a UAV and ground SBS. Then, we derive the successful content delivery probability by considering both the intercell and intracell interference. We also analyze the energy efficiency of the hybrid network and compare it with the separate UAV and ground networks. We further propose the caching scheme to improve the successful content delivery by managing the content popularity, where the part of the caching capacity in each UAV and ground SBS is reserved to store the most popular content (MPC), while the remaining stores less popular contents. Numerical results unveil that the proposed caching scheme has an improvement of 26.6% in content delivery performance over the MPC caching, which overlooks the impact of content diversity during caching.

DIGITAL IMAGE CORRELATION IN ASSESSING STRUCTURED-LIGHT 3D SCANNER’S GANTRY STABILITY: PERFORMING DAVID’S (MICHELANGELO) HIGH-ACCURACY 3D SURVEY

Abstract. The paper presents results from applying Digital Image Correlation (DIC) technique to determine deformations and verify stability on a gantry during surveying operations on the Michelangelo’s David at the Galleria dell’Accademia di Firenze museum in Florence. An advanced hi-resolution Structured-light 3D scanner has been used to create a hi-detailed digital twin of the masterpiece. Considering the high scanner sensitivity, a contactless, remote and passive monitoring system of the gantry stability has been chosen to guarantee maximum freedom of movement around the David and avoid any interference during scanning operations. Due to the remarkable elevation of the statue, which reaches almost 7 meters on his pedestal, and considering the cramped operating area around the statue, an ad-hoc gantry has been designed and deployed. The sophisticated scanner’s technique and the extreme hi-resolution required for the survey needed firm gantry stability during scanning operations from one side. The complex geometries and the considerable extension of the statue surface impose extended flexibility and a nimble elevation platform from the other side. Thanks to the DIC technique the gantry stability has been constantly monitored with an accuracy of 0.03 ÷ 0,04 pixels, optimising scanning scheduling and, consequently, operations efficiency. A comparison of scans with post-processed deformation patterns allowed to optimise the scanning schedule, minimising downtime, and maintaining the needed platform stability threshold for effective scanning.

The rising issue of user manual accessibility: Implications for the safe operation of Elevated Work Platforms (EWPs)

Elevated Work Platforms (EWP) have been implemented as a measure to prevent falls. However, fatalities and injuries relating to EWP use are of concern within the construction industry, with crushing risks often a significant factor in operator fatalities. With a greater number of workers using these machines internationally, it is imperative to develop policies and strategies to guarantee the safe use of EWPs. One key issue is that EWP familiarisation has been primarily centred on the user manual. However, it is unclear if user manuals are an adequate source of education and training in terms of content and readability. To address this research gap, a content analysis was used to assess the differences in content and readability among the manuals of the most used EWPs in Australia. The qualitative findings showed that there are nine safety-related themes in the user manuals, such as control warnings and in-basket safety. The quantitative analysis found that some manuals require several years of education above that recommended for a universal audience (>8 years) to be understood. This finding calls for better training and education across the range of EWP control layouts and standardisation across the methods by which the manuals convey control information to reduce the cognitive load placed on operators to remember and accurately utilise the controls of the wide variety of existing EWPs.

Maternal stress prior to conception impairs memory and decreases right dorsal hippocampal volume and basilar spine density in the prefrontal cortex of adult male offspring

Chronic parental stress impacts offspring functioning throughout life. Chronic variable stress prior to conception impairs offspring development in terms of behavior, neuroanatomy, and neurobiology. Previously, our lab demonstrated that even a consistent stressor experienced by the sire or the dam shapes offspring development beginning in early life. Here, we show how consistent maternal stress prior to conception influences the brain and behavior of offspring in adolescence and adulthood. Female Long-Evans rats were exposed to elevated platform stress twice daily for 27 consecutive days immediately prior to mating with non-stressed males. Male and female offspring were assessed in the open field and elevated plus maze in adolescence, and open field, elevated plus maze, Whishaw tray reaching, and Morris water task in adulthood. Offspring were then euthanized, and their brains were stained with Golgi-Cox solution and then examined for dendritic spine density and hippocampal volume. Major findings include deficits in spatial memory, decreased medial prefrontal cortex spine density, and reduced right dorsal hippocampal volume in male offspring only. This work illustrates that the effects of consistent maternal stress prior to conception are lifelong and highly sexually dimorphic.

Disturbance of resting behaviour of broilers under different environmental conditions

Resting behaviours make up a large part of the daily time budget of broilers. However, in intensive broiler production systems disruptions of resting behaviours occur, where resting individuals get disturbed by active individuals. Such interruptions of resting behaviour may negatively affect the welfare of the birds but also disturb important functions of sleep related for instance to restoration and growth. This study investigated if a lower stocking density or the provision of separate resting places in the form of elevated platforms would result in less disruption of resting patterns of fast-growing broilers. Three different treatments were used, one with an elevated platform, one with lowered stocking density and a control setting. A randomized block design was used, consisting of six blocks, giving six to eight replicates of each treatment. Depending on treatment, 422-497 broilers (Ross 308) were kept per pen. Data on duration of resting bouts, occurrence of disturbances and position in pen during resting were collected on days 20 and 34 of age. An overall effect of treatment x position was found on duration of resting bouts both during day (P < 0.01) and night (P < 0.001). When resting on platforms the duration of resting bouts during daytime was longer compared to when birds were resting in open areas in the control groups (P = 0.04). During night the duration of resting bouts on platforms was longer compared to duration of resting bouts at all other locations in all treatments. In addition, resting position also had an overall effect on proportion of disturbances during day (P = 0.0018) and night (P = 0.0225). Resting on platforms reduced the number of physical disturbances of resting chickens compared to open areas in the control group both during day (P adj < 0.001) and night (P adj = 0.01).Generally, the level of disturbances was high in all treatments, suggesting that birds experience disrupted rest. As rest and sleep are vital needs, it is a welfare concern that chickens negatively affect other individuals’ resting behaviour. A separate resting place appears to reduce disturbances to some extent and thus potentially increases the welfare of broiler chickens. However, provision of platforms is not enough to prevent frequent disturbances of resting and it is concluded that additional changes in housing conditions of broiler chickens are needed to improve their rest and sleep.

Effects of an Elevated Platform on Welfare Aspects in Male Conventional Broilers and Dual-Purpose Chickens.

To avoid killing day-old male chicks, one possibility is to keep dual-purpose chicken strains. Here, the hens were kept for egg production, and the roosters were kept for meat production. Both sexes had moderate performances compared to the respective hybrid chicken strains. However, until now, little has been known about whether male dual-purpose chickens may profit from enrichment in the environment in which broiler chickens are raised under conventional conditions. This study aims to further investigate the suitability of elevated structures for dual-purpose chickens (Lohmann Dual) with moderate growth and for fast-growing male broiler chickens (Ross 308). In two consecutive trials, we kept 686 Ross and 672 Dual chickens in 24 compartments (2 trials × 2 strains × 6 compartments). Half of the compartments were equipped with elevated grid platforms at a height of 50 cm (enriched group). In the other half of the compartments, no platforms were installed (control group). We analyzed the usage of the elevated platforms by scan sampling and assessed animal-based (walking ability, plumage cleanliness, and foot health) and management-based (litter quality) indicators. Both strains showed increasing use of the elevated platforms from the first week of life onwards. However, the fast-growing chickens used the elevated platform less than the slow-growing chickens. At the end of the fattening period, the birds used the elevated grids more at night than during the daytime. Slow-growing chickens kept in enriched compartments showed a better walking ability. In general, slow-growing chickens had better plumage conditions and foot health compared to fast-growing chickens. Our results show that natural behaviors such as perching can be supported by offering elevated platforms and that animal-based indicators such as walking ability can be improved, at least in slow-growing chickens. Moreover, the use of an alternative chicken strain avoids killing day-old male chicks, and in addition, these chickens show fewer animal welfare problems than a conventional fattening strain. Thus, the use of male chickens of a dual-purpose strain can substantially contribute to improving animal welfare in broiler meat production.

Behavioral tagging as a mechanism for aversive-memory formation under acute stress.

The behavioral tagging (BT) hypothesis postulates that a weak learning experience, which only induces short-term memory, may benefit from another event that provides plasticity-related proteins (PRPs) to establish a long-lasting memory. According to BT, the weak experience sets a transient learning tag at specific activated sites, and its temporal and spatial convergence with the PRPs allows the long-term memory (LTM) formation. In this work, rats were subjected to a weak inhibitory avoidance (IAw) training and we observed that acute stress (elevated platform, EP) experienced 1hr before IAw promoted IA-LTM formation. This effect was dependent on glucocorticoid-receptor activity as well as protein synthesis in the dorsal hippocampus. However, the same stress has negative effects on IA-LTM formation when training is strong, probably by competing for necessary PRPs.Furthermore, our experiments showed that EP immediately after training did not impair the setting of the learning tag and even facilitated IA-LTM formation. These findings reveal different impacts of a given acute stressful experience on the formation of an aversive memory that could be explained by BT processes.

Dual vs single force plate analysis of human drop jumping

The aim was to develop a Drop Jump (DJ) protocol on dual force plate recordings (Dual Force Plate method: DFPM) to assess lower limb power production and quantify impact loading, and range of body center of mass (BCM) excursion during human DJ, and to examine if single-plate analysis (Reverse Integration Method: RIM) was a valid alternative. Nineteen male subjects performed DJs from an elevated platform (48 cm). Kinematic (BCM displacement and velocity, rebound jump height) and kinetic (BCM power, work, rate of force development (RFD), lower limb stiffness (LLS)) variables were obtained by force plate recording during the drop take-off phase (DFPM) and rebound phase (RIM, DFPM). DFPM and RIM did not differ at the group level for any outcome parameter. However, large intra-individual differences in BCM displacement were observed between DFPM and RIM (CV 9-10%) as well as for rebound jump height, LLS, and work performed on BCM (CV 9.8-14%). A majority of the remaining variables demonstrated low intra-individual variability between the two methods (r= 0.73-0.96, CV 1-5%). In conclusion, No systematic differences were revealed between DFPM and RIM, suggesting that RIM is a valid approach for assessing DJ performance. Substantial between-method intra-individual variability was noted for key outcome parameters.

Accuracy analysis of multi-baseline InSAR height inversion

Digital elevation model (DEM) is of great significance in commercial and scientific applications, and the accuracy of elevation inversion represents the quality of DEM. With reference to the height measurement accuracy formula of single-baseline interferometric SAR, the mathematical relations between elevation accuracy and platform height, lower viewing angle, target oblique distance, baseline strip number, baseline length and baseline roll angle are established, and the variation of elevation accuracy with system parameters (especially the number of base lines and baseline length) is quantitatively analyzed, and the optimal range of multi-baseline InSAR system parameters is obtained. It provides a theoretical basis for the optimal design of system parameters.

Learning to Assist Drone Landings

Unmanned aerial vehicles (UAVs) are often used for navigating dangerous terrains, however they are difficult to pilot. Due to complex input-output mapping schemes, limited perception, the complex system dynamics and the need to maintain a safe operation distance, novice pilots experience difficulties in performing safe landings in obstacle filled environments. In this work we propose a shared autonomy approach that assists novice pilots to perform safe landings on one of several elevated platforms at a proficiency equal to or greater than experienced pilots. Our approach consists of two modules, a perceptual module and a policy module. The perceptual module compresses high dimensionality RGB-D images into a latent vector trained with a cross-modal variational auto-encoder. The policy module provides assistive control inputs trained with the reinforcement algorithm TD3. We conduct a user study (n=33) where participants land a simulated drone with and without the use of the assistant. Despite the goal platform not being known to the assistant, participants of all skill levels were able to outperform experienced participants while assisted in the task.

Deep-sea submarine erosion by the Kuroshio Current in the Manila accretionary prism, offshore Southern Taiwan

The Kenting Plateau is characterized by unusual low relief surfaces that straddle the topographic crest of the northern Manila accretionary prism off southern Taiwan at 400–700 m water depth. Multibeam bathymetric data, reflection seismic data, Acoustic Doppler Current Profiler (ADCP) data, surface grab samples, and sediment cores were collected in and around the Plateau to identify evidence of erosion in the Kenting Plateau and understand how the morphological evolution has been influenced by submarine erosion over geological time scales. The most distinctive feature on the Kenting Plateau is a 3 km × 7 km bean-shaped flat elevated platform (Kuroshio Knoll) revealed by multibeam bathymetry. Seismic data show almost no reflections beneath the seafloor and erosional truncations at the seafloor, especially in the Plateau's eastern half, evidencing widespread erosion. The P-wave velocity of the gravels recovered from the top of the Plateau ranges from 2.2 to 4 km/s. After comparing the velocity with the borehole data from nearby basin the burial depth of the parent rocks was found to be around 2 to 4 km below the seafloor, indicating that the parent rocks have been uplifted and gravels were formed due to erosion of the Plateau. The truncation of the seafloor shown on seismic sections suggests significant erosion on the Plateau. Sand content of the sediment cores decreases away from the Plateau, suggesting that sediment transport is effective in this area with high energy deposition, thereby accumulating coarse sediments on the Plateau and removing fine particles away from it. The presence of a dune field migrating northward of the Plateau, parallel to the Kuroshio Current also evidences active sediment transport in the area. Flow velocity of the Kuroshio Current observed from the ADCP data is very high, reaching up to 1.8 m/s on top of the Kuroshio Knoll (SE domain). We thus interpret that the observed intense erosion is caused by the Kuroshio Current, while the uplift of the Kenting Plateau is partially due to isostatic rebound caused by sediment removal through erosion and compression of the accretionary wedge. The higher sedimentation rate and coarser in grain size during sea level lowstand (20,000–12,000 yrs. BP) suggests that the erosion was more intense during the glacial period compared to that of deglacial period (< 12,000 yrs. BP) as seen from the MD97–2145 core. Submarine erosion is predominant throughout the Plateau, and it controls the geomorphology of the Plateau, especially the Kuroshio Knoll.

Contributions of prelimbic cortex, dorsal and ventral hippocampus, and basolateral amygdala to fear return induced by elevated platform stress in rats

Fear relapse is a major challenge in the treatment of stress-related mental disorders. Most investigations have focused on fear return induced by stimuli associated with the initial fear learning, while little attention has been paid to fear return evoked after exposure to an unconditioned stressor. This study explored the neural mechanisms of fear return induced by elevated platform (EP) stressor in Sprague-Dawley rats initially subjected to auditory fear conditioning. The contributions of the prelimbic cortex (PL), dorsal hippocampus (DH), ventral hippocampus (VH), and basolateral amygdala (BLA) were examined by targeted bilateral intracerebral injection of the GABAA agonist muscimol after elevated platform (EP) stressor. Muscimol-induced inactivation of PL or BLA significantly impaired the return of conditioning fear, while inactivation of the DH or VH had no effect. These results suggest that fear return induced by non-associative stressor may depend on the PL and BLA but not on the hippocampus.

Acute elevated platform triggers stress induced hyperalgesia and alters glutamatergic transmission in the adult mice anterior cingulate cortex.

Pain is composed of both physiological and affective/emotional components which potentiate one another. In addition, exposure to stress modulates pain and affective behaviors including, anxiety-like behavior and/or depression-like behaviors. Indeed, chronic exposure to stress has been known to enhance stress-induced hyperalgesia (SIH). The anterior cingulate cortex (ACC) is critically involved in pain sensation and emotions. Animal models of chronic pain, but not acute nociception have been found to induce synaptic plasticity on glutamatergic and GABAergic transmission in the rodent ACC. However, it is unclear whether acute stress exposure could produce SIH and cause synaptic plasticity in the ACC. Accordingly, we studied how acute exposure of stress by the elevated open platform (EOP) could affect mechanical threshold, thermal and cold latency in the adult mice. Thirty minutes of the EOP produced mechanical hypersensitivity lasting for 60 min and thermal hypersensitivity immediately after the exposure. Next, we tested whether the stress could alter the excitatory and inhibitory synaptic transmission in the ACC. We performed whole-cell patch-clamp recordings from layer II/III pyramidal neurons in the ACC and analyzed both glutamatergic and GABAergic transmission in mice following the EOP. Thirty minutes of the EOP altered the rise and decay time of spontaneous glutamatergic AMPA/GluK receptors mediated currents, but did not change the frequency or amplitude of excitatory transmission. By contrast, the kinetics of inhibitory synaptic currents were not altered by the EOP. These results suggest that acute stress by the elevated platform produces SIH and causes synaptic plasticity on excitatory transmission, but not inhibitory transmission in the ACC.

Laser Powder Bed Fusion Processing of Fe-Mn-Al-Ni Shape Memory Alloy—On the Effect of Elevated Platform Temperatures

In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.

Quantifying Changes in Surface Elevation in Conjunction with Growth Characteristics of Incipient and Foredune Vegetation

McGuirk, M.T.; Kennedy, D.M.; Konlechner, T., and Chiaradia, A., 2021. Quantifying changes in surface elevation in conjunction with growth characteristics of incipient and foredune vegetation. Journal of Coastal Research, 37(1), 216-224. Coconut Creek (Florida), ISSN 0749-0208. Vegetation is critical for the initiation and growth of incipient dunes and foredunes by providing structure to entrap and store sand. Vegetation characteristics (leaf length, width, height, and quantity) directly influence the rate and volume of sand deposition and therefore the final dune morphology. This paper describes a low-cost and highly portable method to quantify changes in sand surface elevation in relation to plant growth character. A sediment elevation platform was constructed from steel and Perspex, from which surface elevation and plant character can be measured with a movable wooden dowel. This was used in conjunction with a point intercept pin frame to quantify leaf height and number of touches, from which leaf density and frequency were calculated. The system is collapsible, lightweight, and costs AUD 360. It may be operated by a single person. It was tested in a pilot study conducted at Phillip Island, Australia. Plant attributes of two dominant coastal grasses (Spinifex sericeus and Thinopyrum junceiforme) were quantified in December 2018 and January 2019, and sand elevation changes were quantified in January and February 2019. Data collected during the measurement period displayed the influence of plant growth on sand accumulation on a monthly scale. Measurements showed an increase in sand surface elevation from January to February. The average vertical sand accretion for the quadrant with T. junceiforme in January was 29 mm and in February was 89 mm, whereas S. sericeus had an average vertical sand accretion for January of 95 mm and for February of 162 mm. The number of leaves of S. sericeus increased from December (48) to January (169). This new method enables tracking of changes in sand morphology, along with the specific plant growth characteristics. This knowledge may enable the planning of specific dune morphologies using specific plant species and assist in dune recovery after erosion.

Individual differences in the neuroendocrine response of male rats to emotional stressors are not trait-like and strongly depend on the intensity of the stressors

Biological response to stressors is critical to understand stress-related pathologies and vulnerability to psychiatric diseases. It is assumed that we can identify trait-like characteristics in biological responsiveness by testing subjects in a particular stressful situation, but there is scarce information on this issue. We then studied, in a normal outbred population of adult male rats (n = 32), the response of well-characterized stress markers (ACTH, corticosterone and prolactin) to different types of stressors: two novel environments (open-field, OF1 and OF2), an elevated platform (EP), forced swim (SWIM) and immobilization (IMO). Based on both plasma ACTH and prolactin levels, the OF1 was the lowest intensity situation, followed by the OF2 and the EP, then SWIM and finally IMO. When correlations between the individual responses to the different stressors were studied, the magnitude of the correlations was most dependent on the similarities in intensity rather than on other characteristics of stressors, with good correlations between similar intensity stressors and no correlations at all were found between stressors markedly differing in intensity. In two additional confirmatory experiments (n = 37 and n = 20) with HPA hormones, we observed good correlation between the response to restraint and IMO, which were close in intensity, and no correlation between OF1 and SWIM. The present results suggest that individual neuroendocrine response to a particular stressor does not predict the response to another stressor greatly differing in intensity, thus precluding characterization of low or high responsive individuals to any stressor in a normal population. The present data have important implications for human studies.

Training in a virtual environment for high risk work at heights

Falls from a height are a common reason for workplace fatalities in the construction industry. Such high-risk work is likely to remain inherent in construction tasks requiring further efforts to reduce the risk of falling. As an underlying instability in balance may promote the development of height phobia, the current study investigated the role of fear of heights, and individual's postural response (PR) to the perturbation of an elevated work platform while exposed to simulated heights scenarios in virtual reality (VR). Postural responses were measured during the VR training experiment and the Acrophobia questionnaire and motion sickness susceptibility questionnaire were administered. Results indicated that the height anxiety (a sub-scale of the acrophobia questionnaire) was reduced after the 50-minute VR session comprising five trials. Postural response improvement also correlated with decreases in fear of heights. Findings indicate that construction workers may benefit from inclusion of VR exposure to heights as part of preparation to work at heights.

Modelling and characteristics of hybrid coupling hydro-pneumatic suspension for a seven-axle vehicle

A hybrid coupling scheme of parallel connection and contralateral cross-linking was proposed based on the characteristics of high centroid position and low rollover threshold on hydro-pneumatic suspension (HPS) for a seven-axle elevated platform vehicle. A dynamic model with 20 DOFs which can comprehensively reflect vehicle coupling vibration including vertical-lateral-longitudinal-transverse and the joint simulation model of Simulink and AMESim were established based on the structural characteristics of the vehicle. Furthermore, the random road surface model linking the wheels was constructed by filter shaping white noise. Based on the model of hybrid coupling HPS, the study of joint simulation and test on the whole vehicle were conducted, and improved ant colony algorithm (IACA) was applied to the multi-objective optimisation study of HPS parameter matching. The comparison between simulation and test data shows that the weighted acceleration PSD curve is in good agreement, and the relative error of weighted acceleration RMS is small, which indicated that the theoretical model was accurate. The results of simulation and testing show that the optimal parameter matching scheme output by IACA can improve vehicle ride comfort and stability to a significant extent.

Effect of pens with an elevated platform on space utilization, skin lesions and growth performance in nursery pigs

Environmental enrichment, adequate space and the ability to separate a living area into suitable functional areas are key elements for pig welfare. In this study, a two-level pen for nursery pigs was explored with the aim of analysing the use of space and the impact on pig behaviour, health and performance. Therefore, per batch, three experimental groups in pens with elevated platforms (two-level pens) and one control group in a standard pen were formed after weaning at the age of 4 weeks. Thereafter, groups were studied for a period of 6 weeks. In a total of eight batches (n = 882 pigs), the occurrence of skin lesions was determined per individual using a lesion score, and in seven batches (n = 761 pigs) individual daily weight gain was analysed. In five batches (n = 450 pigs), the individual use of space and the behaviour of pigs were investigated by direct observation (4 h per day on 2 days in weeks 1, 3 and 6 of the housing period, respectively). Results revealed that 98.9% of pigs (n = 445) were observed on the elevated platform at least once. The probability that an individual pig used the platform was significantly higher than 0.95 (P < 0.0001, confidence interval = 0.977, 1). The use of the platform was not affected by sex (odds ratio (OR) = 1.013, P = 0.937). However, the probability of observing an individual on the elevated platform increased with increasing BW during the experimental period (OR = 1.043, P < 0.0001). The presence of a platform decreased the probability of seeing a pig fighting (P = 0.014) and increased the probability of observing locomotor behaviour as opposed to lying (P < 0.0001). In two-level pens, pigs sustained fewer skin injuries than in standard pens (day 41: OR = 0.731, P < 0.0001). Over 41 days of experiment, pigs in two-level pens had higher daily weight gains than animals in standard pens (416 versus 393 g/day, P = 0.006). We conclude that usable space for nursery pigs can be effectively extended by introducing elevated platforms into the pigs’ pen. Furthermore, pigs may benefit from two-level systems by establishing spaces for activity as well as for retreat from other pen mates, thereby reducing aggressive behaviour and social stress. The installation of two-level pens is therefore encouraged, if they are intended to provide more space than legally stipulated.