Ian J.H. Duncan

The effects of weaning at 7, 14 and 28 days on piglet behaviour

Abstract There has been a trend in North America towards very early weaning of piglets combined with a segregation of the piglets from the sow in a system known as Segregated Early Weaning (SEW). This paper investigates the effects of very early weaning on piglet behaviour. In order to determine the effects of weaning age on piglet behaviour, litters of piglets were randomly assigned to be weaned at 7, 14, and 28 days of age. In each of three trials, piglets from three litters were mixed into two pens of 10 piglets per weaning age (six replicates per treatment, N =180). Pens were video-taped for 2 days immediately post-weaning and periodically until piglets were 6 weeks of age. There were marked differences in the behaviour of the piglets weaned at the different ages. Piglets weaned at 7 days spent more time belly-nosing ( P P P P P P P P P

Free and operant feeding in domestic fowls

Abstract Domestic fowls, when given access to ad libitum food in a Skinner box, preferred to obtain at least part of their diet by working for it. Habit strength, degree of hunger, time of day and “boredom” all appeared to exert little influence on the expression of this phenomenon, although three were large and consistent differences between individual birds. There was a trend over the whole experimental period for the mean proportion of food earned to increase.

BEHAVIOURAL CONSEQUENCES OF PARTIAL BEAK AMPUTATION (BEAK TRIMMING) IN POULTRY

1. The effects of beak trimming on 16-week-old Brown Leghorn hens, housed individually in battery cages, was assessed by comparing their behaviour after trimming with their behaviour before trimming and with the behaviour of a sham-operated control group. 2. In the short-term, times spent feeding, drinking and preening decreased. 3. In the long-term, times spent preening and pecking at the cage decreased and times spent standing inactive increased, with no signs of returning to pretreatment values after 5 weeks. 4. During the first three weeks, times spent feeding and drinking decreased and during the first two weeks, times spent sitting dozing increased, but after 5 weeks these had returned to near pre-treatment values. 5. It is argued that pain is the most probable cause of these behavioural changes. 6. The decrease in welfare to the individual bird caused by this pain will conflict with any increase in welfare to the flock brought about by beak trimming; this should be considered before any decision to beak trim is taken.

Behaviour of young domestic fowl directed towards different substrates

Abstract 1. Eight groups of 6 female ISA Brown chickens of 43 d of age, housed in pens on wood shavings, were used. Each group was given access for 30 min daily for 8 d to 4 trays, each containing a single substrate: peat, sand, sawdust and wood shavings. The behaviour directed towards these substrates was observed and recorded. 2. Although there was variation between pens of birds, peat and wood shavings were used most for ground scratching, ground pecking and resting. 3. Significantly more bouts of dustbathing took place in the peat than in the other substrates (P<0.001). The bouts were also significantly longer in duration in peat (P<0.001). 4. After short dustbathing bouts in other substrates, birds switched to using peat on 12 occasions, compared with 6 occasions when they switched away from peat. 5. Differences in the use of different substrates may explain the variation in the findings of previous studies on dustbathing. It is suggested that workers should be more specific in their descriptions of ...

What’s in a peck? Using fixed action pattern morphology to identify the motivational basis of abnormal feather-pecking behaviour.

Like many captive animals, hens, Gallus gallus, used for agricultural production perform abnormal behaviours. They are particularly prone to feather pecking, the severest form of which involves the pecking at and removal of feathers, which can cause bleeding and even stimulate cannibalism. The two main hypothesized explanations for feather pecking concern frustrated motivations to forage or, alternatively, to dustbathe, leading to redirected behaviour in the form of pecks at plumage. Previous work on pigeons has shown that the detailed morphology of pecks involved in drinking and feeding, or in working for food or water, involves motivationally distinct ‘fixed action patterns’. We therefore used methods similar to these fixed action pattern studies to quantify the motor patterns involved in foraging and in dustbathing pecks, for comparison to feather pecking. We videoed 60 chickens pecking at a variety of forages and dustbaths, along with novel objects, water and bird models that could be feather pecked. We recorded the durations of the head fixation before the peck, between the head fixation to beak contact with each stimulus and of the whole peck sequence. We used mixed models to assess whether the motivation underlying a peck affected its morphology and whether severe feather pecks resembled or differed from either dustbath or foraging pecks (or even novel-object pecking or drinking). The motor patterns involved in pecks at forages, dustbaths, novel objects and water all varied significantly; importantly, the motor patterns involved in pecking during dustbathing and foraging differed (P 0.95) but different from all other pecks, including dustbathing (P < 0.0001 for all measures). These results indicate that severe feather pecking derives from frustrated motivations to forage, not to dustbathe. More broadly, they suggest that finely analysing fixed action pattern morphology can help elucidate the motivational bases of puzzling abnormal behaviours in captive animals.

The pros and cons of cages

The main advantages of battery cages for laying hens over alternative husbandry systems are (1) increased hygiene resulting in a much lower incidence of diseases in which the infectious agent is spread through the droppings, (2) small group size resulting in a low incidence of social friction, (3) ease of management, (4) absence of litter problems, (5) better working conditions, and (6) a much lower cost of production. The disadvantages are (1) lack of physical and psychological space for the hens, (2) lack of exercise resulting in a higher incidence of metabolic disorders, (3) lack of nesting opportunities resulting in severe frustration for many birds each time an egg is laid, (4) lack of dust bathing opportunities which, although not a severe disadvantage, should still be charged to cages, (5) lack of other behavioural opportunities which again seem not to be a severe disadvantage and which await further elucidation, and (6) a higher incidence of foot lesions.

External factors and causation of dustbathing in domestic hens.

Dustbathing is known to be motivated by complex interactions between internal factors which build up over time and external factors, such as the sight of a dusty substrate. In this study, the effects of other external factors were investigated. Environmental temperature was shown to be important; frequencies of dustbathing were greater when hens were held at 22 than at 10°C (P<0.01). In a second experiment, a radiant heat source or a radiant heat+light source, balanced to give the same radiant heat, resulted in more dustbathing behaviour during a 1-h stimulus period than during the same period with no stimulus (P<0.05). Components of dustbathing were increased more by the heat+light stimulus than by the heat stimulus alone (P<0.03). In a third experiment, the amount of dustbathing performed by individual hens in cages with dustbaths was increased by the presence of a group of hens dustbathing in an adjoining pen with a dustbath compared with the amount occurring when the hens were absent from the pen.

Frustrated nesting behaviour: Relation to extra-cuticular shell calcium and bone strength in White Leghorn hens

1. The inability of hens to express normal nesting behaviour in battery cages results in frustration, manifesting itself as stereotyped pacing. Frustration can cause hens to retain their eggs beyond the expected time of lay, resulting in an extra-cuticular layer of calcium on eggshells. 2. This study investigated whether frustrated nesting behaviour caused extra-cuticular calcification of eggshells and whether this loss of non-structural calcium to eggshells may have subsequently contributed to weak bones in spent hens. 3. One hundred and twenty hens were assigned to one of three treatments: NB (hens given nest boxes in their cages), NN (no nest box) and R (access to nest box periodically restricted). 4. NB hens spent the least amount of time pacing in the hour before oviposition. NN and R hens spent similar amounts of time pacing. 5. Contrary to expectation, eggshells from hens under different treatments yielded the same amount of extra-cuticular calcium. Similarly tibia strength did not significantly differ among treatments.

Using time to insensibility and estimated time of death to evaluate a nonpenetrating captive bolt, cervical dislocation, and blunt trauma for on-farm killing of turkeys

The effectiveness of a pneumatic nonpenetrating captive bolt (Zephyr) was assessed for on-farm euthanasia of turkeys and compared with blunt force trauma, manual cervical dislocation, and mechanical cervical dislocation using a burdizzo. The Zephyr (n = 46) and burdizzo (n = 26) were evaluated in turkey hens (11.4 +/- 0.1 kg), the Zephyr (n = 46) and blunt trauma (n = 32) were evaluated in turkey toms (13.1 +/- 0.2 kg), and the Zephyr (n = 12), blunt trauma (n = 11), and manual cervical dislocation (n = 7) were evaluated in broiler turkeys (4.1 +/- 0.3 kg). The nictitating membrane and pupillary light reflexes were monitored continuously to determine when insensibility occurred. Time of death was estimated based on the end time of convulsions and sustained absence of breathing. The nictitating membrane reflex was present immediately after treatment in all 26 hens killed with a burdizzo versus 8 of 46 hens killed with the Zephyr (P < 0.001). The presence of eye reflexes did not differ between the Zephyr and blunt trauma for toms (1 of 26 toms killed with blunt trauma, 2 of 44 toms killed with the Zephyr, P = 1.0). The nictitating membrane reflex persisted in a greater proportion of broiler turkeys killed with cervical dislocation (7 of 7) versus the Zephyr (0 of 12, P < 0.001) and blunt trauma (2 of 9, P = 0.003) but did not differ between blunt trauma and the Zephyr (P = 0.2). End time of convulsions did not differ between the Zephyr and burdizzo for hens (204 +/- 8 vs. 114 +/- 10 s, P = 0.5) or between the Zephyr and blunt trauma for toms (200 +/- 7 s vs. 218 +/- 11.8 s, P = 0.4) but was shorter after cervical dislocation in broiler turkeys (cervical dislocation: 138 +/- 13 s, Zephyr: 165 +/- 7 s, blunt trauma: 178 +/- 13 s, P < 0.001). Results demonstrated that the Zephyr (discharged twice in immediate succession) and blunt trauma (single hit) were similarly effective at consistently causing immediate insensibility. Conversely, neither method of cervical dislocation caused immediate insensibility. This study may assist in revising current poultry euthanasia recommendations.

Why do hens sham dustbathe when they have litter

Abstract Hens in cages perform sham dustbathing, that is they go through the behavioural sequence of dustbathing, but on the wire-floor. Such sham dustbathing is found in conventional cages and even in furnished cages which include a dustbath. Consequently, sham dustbathing behaviour cannot be explained only by the absence of litter. Three suggested explanations for sham dustbathing were tested in this study. The first hypothesis was that sham dustbathing satisfies the hens’ motivation for dustbathing behaviour. This hypothesis was investigated by allowing litter-deprived hens to dustbathe, sham dustbathe or simply see dust but not dustbathe, and then measuring dustbathing behaviour when the hens were subsequently given access to litter. No reduction in dustbathing was found after sham dustbathing. The second hypothesis was that sham dustbathing may be the result of social facilitation combined with the fact that the dustbath in furnished cages rarely allows more than one hen to dustbathe at a time. If other hens observing a hen dustbathing in the dustbath become more motivated to dustbathe themselves, they may have to sham dustbathe on the floor. We tested this hypothesis by exposing litter-deprived hens to three different stimuli; hens dustbathing in litter, hens on litter but not dustbathing, and hens without litter and not dustbathing. There was no difference in the amount of sham dustbathing performed by the test hens in the different stimulus situations. Thus, neither the satisfaction from sham dustbathing nor the effect of social facilitation seem to explain why hens sham dustbathe in the presence of a dustbath. If the hens are prevented from dustbathing as chicks, or as pullets when first moved to the furnished laying cages, they may persist in sham dustbathing even if a dustbath is made available to them. The third hypothesis, therefore, was that there is an effect of habit or early experience. To test this hypothesis, hens were deprived of litter until they had developed sham dustbathing and were then given access to litter in a different location to that used for sham dustbathing. In this experiment, six hens (of a total of 26 deprived hens) showed sham dustbathing although litter was available. Thus, some support was found for an effect of habit or early experience on sham dustbathing. This finding is discussed in the light of other research on the effect of experience on dustbathing behaviour.