Effects Of Beak Trimming Research Articles

Effect of beak trimming at hatch and oat hulls inclusion in the diet on growth performance, preference behaviour for coarse particles and gastrointestinal tract traits of brown-egg pullets from 1–35 days of age

The effects of infra-red beak treatment (IRBT) at hatch and the inclusion of oat hulls (OH) in the diet on growth performance, water intake (WI), preference behaviour for coarse particles and the development of the gastrointestinal tract (GIT), was studied in brown-egg pullets from 1 to 35 days of age. The experimental design was completely randomized with 4 treatments arranged as a 2 × 2 factorial with beak treatment (IRBT vs. sham) and OH inclusion (0 vs. 30 g/kg diet) as main effects. Each treatment was replicated 20 times and the experimental unit was a cage with 10 pullets. Growth performance and water intake were determined by week and cumulatively. Preference behaviour for coarse particles and the development of selected organs of the GIT, were determined at 28 and 35 days of age, respectively. No interactions between IRBT and OH inclusion were detected for any of the traits studied at any age, and therefore, only main effects are discussed. Cumulatively (1–35 days of age), IRBT increased mortality (P<0.01) and reduced feed consumption (P<0.001), body weight (BW) gain (P < 0.01) and water intake (P < 0.001), but improved feed conversion (P < 0.001) of the pullets. Oat hulls inclusion did not affect BW gain, BW uniformity or energy conversion ratio, but reduced pullet mortality (P = 0.099) and water to feed ratio (P < 0.05). The interactions detected between age and IRBT on pullet performance were numerous. From 1–21 days of age, BW gain was better for the sham than for the IRBT pullets but an opposite effect was observed from 29 to 35 days of age (P < 0.01). Similarly, from 1 to 28 days of age, BW uniformity and WI were higher for the sham than for the IRBT pullets but no differences were detected from 29 to 35 days of age. Preference behaviour for coarse particles, measured at 28 days of age, was greater for the sham than for the IRBT pullets (P < 0.001). In summary, infra-red beak treatment increased mortality from 1 to 7 days of age and reduced pullet performance from 1 to 28 days of age but not thereafter. Young pullets show a clear preference to consume coarse particles. Oat hulls inclusion increased feed intake and decreased mortality and water to feed ratio of the pullets but did not affect energy efficiency or the development of the gastrointestinal tract.

Effect of beak trimming on cannibalism and mortality of Kadaknath chickens

Effect of beak trimming on cannibalism and mortality of Kadaknath chickens

Effect of beak trimming at hatch and the inclusion of oat hulls in the diet on growth performance, feed preference, exploratory pecking behavior, and gastrointestinal tract traits of brown-egg pullets from hatch to 15 weeks of age

The influence of infrared beak trimming at hatch (IRBT) and the inclusion of oat hulls (OH) in the diet on growth performance, feed preference, exploratory pecking behavior, and gastrointestinal tract (GIT) development, was studied in brown-egg pullets from 0 to 15 wk of age. The experimental design was completely randomized with 4 treatments arranged as a 2 × 2 factorial with IRBT (sham vs. treated) and OH inclusion (0 vs. 3%) as main effects. Each treatment was replicated 20 times and the experimental unit was a cage with 10 pullets. Feed intake (FI), BW gain, feed conversion ratio (FCR), energy intake (EI, kcal AMEn/d), and energy conversion ratio (ECR, kcal AMEn/g of BW gain) were determined by feeding period (0 to 6, 7 to 10, and 11 to 15 wk of age) and cumulatively. Particle size preference was measured at 7 wk and exploratory pecking behavior of the pullets and at 8 to 14 wk of age. From 0 to 6 wk of age, beak trimming decreased FI (P < 0.01) and increased pullet mortality (P < 0.001) but did not affect BW gain. From 0 to 15 wk of age, OH inclusion improved BW uniformity (P = 0.090) but impaired FCR (P < 0.05) without showing any effect on BW gain or ECR. Preference for coarse particles was greater for the sham than for the treated pullets. Beak trimming and OH feeding reduced (P < 0.05) the exploratory pecking behavior of the pullets from 8 to 12 wk of age but not thereafter. Oat hulls increased the relative weights of the full gizzard and intestines at all ages (P < 0.05). In summary, beak trimming did not affect pullet performance at 15 wk of age or GIT development at any age. Oat hulls improved GIT development at all ages but did not affect BW or ECR. Both beak treatment and OH inclusion affected particle size preference and reduced the exploratory pecking behavior of the birds.

Influência de métodos de debicagem e do tipo de bebedouro no desempenho e na qualidade dos ovos de codornas japonesas

Com o objetivo de avaliar o efeito da debicagem e do tipo de bebedouro sobre o desempenho produtivo de codornas japonesas, 672 fêmeas de codornas de um dia foram usadas em um delineamento inteiramente casualizado e distribuídas em um dos três tratamentos como não-debicagem; debicagem até 1/3 dos bicos; e cauterização, com oito repetições de 28 aves na fase de cria. As aves foram debicadas aos 21 dias de idade e, no 35 dia, foram avaliados o ganho de peso, o consumo de ração, a conversão alimentar e a taxa de mortalidade. Aos 39 dias, 576 codornas foram remanejadas para gaiolas de postura, distribuídas em esquema fatorial 3 × 2, composto de três tipos de debicagem e dois tipos de bebedouro (taça e nipple), de modo que cada combinação foi avaliada com quatro repetições de 24 aves. A fase de produção teve início quando as aves atingiram 50% de produção de ovos, aos 60 dias de idade. As codornas submetidas a debicagem por cauterização apresentaram menor ganho de peso e menor consumo de ração na fase de cria. O estresse pela dor com a debicagem por cauterização pode justificar não só o menor consumo e o menor ganho de peso, como também a maior mortalidade. Infere-se que este método, por ser mais demorado, tenha provocado mais dor e maior nível de estresse, piorando o desempenho das aves. A debicagem de 1/3 dos bicos cortados pode ter ocasionado estresse menos intenso às aves, não interferindo no desempenho. Não se observaram diferenças no desempenho das aves e na qualidade de ovos entre os tipos de bebedouro e métodos de debicagem utilizado na fase de produção. O método de debicagem por cauterização influencia o desempenho de codornas na fase de cria, mas, na fase de produção, assim como o tipo de bebedouro utilizado, não interfere no desempenho das aves nem na qualidade de ovos.

Effects of Beak Trimming on Pecking Force

Beak trimming of the production laying hen has come under great scrutiny by welfare and consumer advocacy groups as a potential source of acute and chronic pain as well as having the potential to inhibit the freedom to express normal behaviors such as feeding behaviors. Although several studies have shown evidence of immediate pain response from beak trimming, the long term effects on bird welfare are not well understood. In the present study we investigated the force with which chicks peck during feeding. Chicks were beak trimmed using hot blade trimming at 2 days of age and were tested on a force plate at 3, 4 and 5 weeks of age. Both the time spent pecking and the forces of those pecks were measured. Beak trimmed birds spent significantly less time pecking at the feed and used less force than untrimmed birds at 3 weeks of age (p 0.05). Beak trimmed birds also had a higher pecking ratio (peck force:time, p 0.05). Our data suggest that beak trimming alters feeding behavior at a young age. However, changes in pecking force and time spent feeding were not long lasting and became similar to those of untrimmed birds after 3 weeks post-trimming.

Relationship Between Body Weight and Beak Characteristics in One-Day-Old White Leghorn Chicks: Its Implications for Beak Trimming

Beak trimming is a routine practice used in laying hens to prevent feather pecking and cannibalism. The effect of beak trimming on bird well-being depends on multiple factors, including the amount of beak that is trimmed and the quality of the procedure. The aim of this work was to determine if a relationship existed between BW and beak characteristics in 1-d-old chicks, with a future aim to develop an automated system for standardizing beak trimming. Three hundred forty-four 1-d-old chicks (Hy-Line W-36) were sorted into 3 categories based on their BW (heavy, intermediate, and light), and their beaks were photographed. Dimensional measures of beaks, including the lengths of the culmen, gonys, maxillary tomia, mandibular tomia, and the width of the upper mandible and lower mandible measured at 2, 3, and 4 mm from the tip of the upper and lower beaks, were calculated using imaging software. Correlations between BW and beak measures were evaluated using Pearson product-moment, Spearman rank-order, Kendall's tau, and Hoeffding's dependency tests. Results showed there were no significant correlations between beak dimensions and BW in the light BW group. In contrast, correlations were present between BW and the width of the upper mandible measured at 4 mm from the tip of the upper beak (P < 0.05) and the width of the lower mandible measured 2 to 4 mm from the tip of the lower beak (P < 0.05) in the intermediate BW group. In the heavy BW group, BW was positively correlated with mandibular tomia, gonys, and the width of the lower mandible measured at 2 mm from the tip of the lower beak (P < 0.05). However, in general, these correlations were too low (all below 0.23) to have any practical use for predicting beak size. Overall, the data indicated that BW cannot be used as a reliable predicator of beak size in 1-d-old Hy-Line W-36 chicks.

Effects of beak trimming and cage design on laying hen performance and egg quality

1. Conventional cages are to be replaced by furnished cages or aviary systems to improve the welfare of hens. We compared the performance and egg quality of hens reared in two designs of furnished cages and of two standard cages. We also explored the consequences of the absence of beak trimming when using these designs. 2. Hens (2028) were housed from 18 to 70 weeks of age in 108 standard cages at 6 per cage (60 cm × 63·5 cm), in 96 cages at 5 per cage (59·5 cm × 55·5 cm) or in two designs of furnished cage at 15 per cage (24 F15M cages and 36 F15P cages made by two manufacturers) which contained equipment varying in size and location (nests, dust baths and perches). Half of the hens were beak-trimmed in each design. 3. Mortality was low in beak-trimmed hens (<5%) but was unacceptably high in non-beak-trimmed hens due to cannibalism (>40%, 516 hens). Mortality was worse in standard cages than in furnished cages. Consequently, hen-housed egg production was significantly lowered in non-beak-trimmed hens. 4. Egg laying in beak-trimmed hens reared in furnished cages occurred mainly in the nest (80 and 84·8% in F15M and F15P) but also in the dust bath (13·3 and 9·4% in F15M and F15P) and in other parts of the cage (6·7 and 5·8% in F15M and F15P). 5. The total percentage of broken (visual observation) and hair-cracked eggs (candling) was high in the furnished cage designs (15·4 and 19·6% in F15M and F15P, respectively) compared with standard cage designs (8·1 and 12·2% in S6 and S5). This was mainly due to hair-cracked eggs, the highest percentages occurring in the nests, especially in the design with a narrow nest and no egg saver (11·1% in F15M compared to 17·6% in F15P) as a consequence of egg accumulation in the cradle and relatively low frequency of manual egg collection. 6. Eggshell quality (index and breaking strength) was only slightly influenced by cage effects so differences in egg breakage were attributable to impacts related to cage design. 7. It is concluded that beak trimming remains the most effective way to prevent cannibalism, although furnished cages with a large group of hens slightly reduced the incidence, and that further development and optimisation of furnished cages is needed to reach egg quality similar to standard cages.

Ontogeny of behaviour in intact and beak trimmed layer pullets, with special reference to preening

1. The effects of commercial beak trimming on layer pullet behaviour were investigated, with special reference to preening. 2. One-d-old chicks, 96 in all, were housed in 12 litter floor pens, with 8 birds in each, to 20 weeks of age. Approximately one quarter of the beak was trimmed in all birds in half of the pens (BT) at 8 d of age using a hot blade debeaker. The birds in the other pens remained intact (NBT). 3. There was no significant effect of beak trimming on body weight at any age. At the end of the study, upper mandible lengths were shorter in BT birds. 4. Beak trimming had very little effect on behaviour. NBT birds showed more litter-directed behaviour than did BT birds, and BT birds spent more time in preening directed at the preen gland, and at the back while sitting. 5. Feather damage was minimal and there was no difference in mean feather damage scores between treatments at any age. 6. The young age and small amount of beak removed during beak trimming may be at least partly responsible for the lack of effects of beak treatment on behaviour and plumage condition.

The Effect of Beak Trimming on Two Strains of Commercial Tom Turkeys.: 2. Behavior Traits

The influence of beak trimming of two strains of commercial male turkeys (Strains A and B) on behavior during the growing period was investigated. Poults were either left with beaks intact or arc beak trimmed at hatching. Strain by beak treatment interactions were generally lacking, indicating that these two strains responded similarly. Beak trimming did not influence tameness (as measured by response to a novel object at 16 wk), fearfulness (as measured by tonic immobility response at 18 wk), or resting behavior from 3 to 15 wk of age. When compared to birds with intact beaks, birds with trimmed beaks spent more time standing during the week of hatching and were observed eating more often at 2 wk of age. Strain B birds were more tame, less fearful, and rested more at 8 and 11 wk of age than Strain A birds. Results of the current study indicate that the influence of arc beak trimming at hatching on behavior of male turkeys is transitory. Arc beak trimming of male turkeys at hatching did not appear to have a lasting negative impact on their well-being.

The Effect of Beak Trimming on Two Strains of Commercial Tom Turkeys: 1. Performance Traits

Two commercial strains (Strains A and B) of tom turkeys were either beak trimmed or left with intact beaks. These strains responded similarly to beak trimming for performance traits, with the exception of a higher incidence of beak-inflicted injuries among Strain B toms with intact beaks. Turkeys with trimmed beaks had higher body weights at 8, 12, and 16 wk. Feed efficiency was better in beak-trimmed birds from 4 to 8 wk, 12 to 16 wk, and 0 to 18 wk. Beak treatment did not effect mortality. Leg abnormalities caused the majority of culling or resulted in death or culling from beak-inflicted injuries. Beak trimming seems to be a beneficial practice in tom turkeys because feed efficiency of beak-trimmed toms was improved and injuries were reduced in a strain that tended to exhibit a high degree of beak-inflicted injuries. The results suggest that the need for beak trimming tom turkeys may be reduced when feed efficiency of toms with intact beaks is improved.

Effect of Beak Trimming, Blade Temperature, and Age at Beak Trimming on Performance of Two Strains of Egg Layers

Two experiments were conducted to study the effects of beak trimmer blade temperature (BT) and age at precision beak trimming (PBT) on the performance of two commercial strains of egg layers: Babcock B300® and Hy-Line W36®. The birds were housed in cages during the rearing and laying periods. In Experiment 1, only feed consumption was significantly affected by BT during the rearing periods. The chicks PBT at 10 days 1450°F consumed 1.5g more feed per chick day to 18 wk than 1200°F chicks. The treatments had no significant effects on hen-day egg production, feed efficiency, or mortality during the laying period. There were significant strain × BT temperature interactions. The two strains differed more when compared for feed efficiency and mortality at 1450°F than at 1200°F. In Experiment 2, PBT at 7 or 10 days of age and 1000°F or 1200°F had no significant effect on feed consumption, body weight, or mortality during the rearing period and hen-day egg production and feed efficiency during the laying period. At 16.5 wk of age, the combined average upper and lower beak lengths for PBT birds were 61 and 100%, respectively, those of untrimmed birds (UT). The UT birds produced significantly fewer grams of egg per gram of feed (0.02) with higher mortality (5.1%) than the PBT birds.

Research Note: Effects of Beak Trimming and Genetic Stock on Rate of Mash Consumption and Feeding-Related Behavior in Egg-Strain Pullets ,

Pullets whose beaks were trimmed once (at 9 days) and twice (at 9 days and 9 wk) were able to ingest feed, in the form of mash, more rapidly under competitive feeding conditions and at least as rapidly in the absence of competition as pullets with intact beaks. Tests of feeding rate, when pullets fed in groups, were carried out after a feed deprivation period of 7 h at ages of 10 through 16 wk. Similar tests were done at 18 wk, when pullets fed without competition.Genetic stock and age had significant effects on frequency of agonistic acts at the feeder and displacements from the feeder during 5-min tests under competitive feeding conditions. Age influenced the number of pullets feeding simultaneously and amount of feed eaten per pullet during the same feeding tests. No interactions were detected among beak treatment, stock, and age for feeding-related behaviors or rate of feed consumption during competitive feeding. In noncompetitive feeding tests, genetic stock affected feeding rate but no stock by beak treatment interaction was present.

Beak Trimming Effects on Beak Length and Feed Usage for Growth and Egg Production ,

Two experiments were conducted to compare beak treatment effects on pullets of three genetic stocks. Within each stock, equal numbers were assigned to three treatments: no beak trimming (IN), beak trimming once (1X), and beak trimming twice (2X). Beak treatment, genetic stock, and age effects along with interactions among main effects were examined for production-associated traits during rearing and brief periods of early egg production.Beaks of 1X and 2X pullets remained shorter than those of IN pullets through final measurements at 36 and 32 wk of age in Experiments 1 and 2, respectively. However, differences in beak length decreased as age increased. Upper beaks of 2X pullets remained shorter than those of 1X pullets, but lower beaks of 1X and 2X pullets did not differ by 20 wk in Experiment 2.Weight gains, feed usage, and efficiency of growth were affected by beak treatments. Beak trimming reduced gains, feed eaten, feed wasted, and total feed used, and 2X pullets used their feed more efficiently for weight gain and egg production. A general decrease occurred in differences among beak treatments for weight gains, feed eaten, feed wasted, and efficiency of gains with increasing age during rearing. Nevertheless, significant differences in feed consumed, feed wasted, and efficiency of feed used for egg production indicated an economic advantage in favor of beak trimming.

Beak Trimming and Sex Effects on Behavior and Performance Traits of Large White Turkeys

The effects of beak trimming at day old on performance and behavioral activities of male and female Large White turkeys were evaluated. One hundred and twenty poults of each sex were evenly assigned to 20 treatment pens and evaluated for body weight, feed usage, and livability characteristics to 18 wk of age. Behavioral observations were conducted for feeding, drinking, sleeping, huddling, resting, and agonistic activities.Beak trimming affected body weight and feed usage levels for the sexes differently. From 6 wk, trimmed males were significantly heavier than untrimmed males, whereas untrimmed females were heavier than trimmed females from 12 wk. Similar to body weights, feed usage levels from 13 to 18 wk were higher for trimmed males compared with untrimmed males and lower for trimmed females compared with untrimmed females. Feed conversion ratios after 12 wk and survival to 18 wk were not affected by trimming treatment. Livability rates, however, were lowest for untrimmed males and highest for untrimmed females.Effects on behavioral activities were confined primarily to the brooding and early rearing phases. Beak trimming reduced feeding activity of females and drinking activity of both males and females during the first 2 wk. Sleeping, huddling, and resting activities were increased by beak trimming for both sexes during brooding. Agonistic acts were reduced by beak trimming main effect at 3 and 6 wk. Trimmed males committed fewer agonistic acts at 6 wk than untrimmed males.

Selection and Beak-Trimming Effects on Behavior, Cannibalism, and Short-Term Production Traits in White Leghorn Pullets ,

Pallets of stocks derived from the North Central Randombred White Leghorn population without selection (C) or selected (S) on family performance when kept with beaks intact in multiple-hen cages were compared. Pullets had intact, one-fourth, or one-half of the beak removed (IN, 1/4R, and 1/2R, respectively). No stock differences were detected for behavior traits or other measures during the rearing period. However, beak-trimmed pullets were more inactive and feeding behavior was depressed in 1/2R pullets 1 wk after beak trimming.At 16 wk, 1/4R pullets' beaks had regrown but 1/2R pullets' beaks continued to be shorter than IN pullets' beaks. No differences in fearfulness were found between genetic stocks or among beak length treatments early in the laying period. Deaths from beak-inflicted injuries accumulated steadily from 18 wk until the study was ended at 40 wk. Cannibalistic deaths occurred less frequently in S as compared with C pullets within each beak treatment. As the amount of beak removal increased, beak-inflicted mortality decreased.The S pullets had earlier sexual maturity, lighter egg weights, and greater hen-housed egg production and egg mass than C pullets, and 1/2R pullets had greater egg production than 1/4R and IN pullets. Genetic stock by age and beak treatment by age interactions were present for hen-housed production and egg mass, and the interactions appeared to result primarily from increased mortality from cannibalistic pecking with increased age.

Beak Trimming Effects on Behavior Patterns, Fearfulness, Feathering, and Mortality Among Three Stocks of White Leghorn Pullets in Cages or Floor Pens ,

White Leghorn pullets of the Y1, Y2, and North Central Randombred (NCR) experimental stocks were used. Half of the birds of each stock had half of the upper and less of the lower mandible removed at 4 wk of age by making a V-shaped cut as viewed from the side (BT), whereas the other half retained their beaks intact (IN). Pullets were moved from growing pens to a layer house at 18 wk of age. Seventy-two cages and 30 floor pens were filled with 6 and 20 birds per unit, respectively. Pullets within a cage or floor pen were all of the same genetic stock and beak treatment. All measurements were performed within 10 wk after housing, except for mortality in cages.When kept in cages, genetic stocks did not show behavioral differences. However, in floor pens, stock differences were detected in feeding, crouching, and nonaggressive pecking. When kept in cages, the stocks also differed in 24-wk body weight, weight gain from 18 to 24 wk, and certain measures of fearfulness in both cages and pens, and in feather condition at 21 and 22 wk. Mortality from cannibalism and hen-days survival of caged IN pullets differed among genetic stocks. Mortality from cannibalism was absent among pullets kept in experimental floor pens.In cages, BT pullets were less active, gained less weight, and had lower incidence of cannibalism than IN pullets. Also, BT pullets were less nervous and had better feather condition than IN pullets. However, trimming beaks to prevent cannibalism was less effective in NCR pullets than in Y1 or Y2 pullets.In floor pens, BT pullets showed less activity and reduced feeding frequency and less fearfulness as indicated by duration of induced tonic immobility. Agonistic behaviors were not different between BT and IN pullets.From these results, beak trimming could be interpreted as having either stressful or stress-alleviating effects, depending on the criteria used. However, proper beak trimming appears beneficial when cannibalistic pecking is likely to be a problem. The relative benefits of beak trimming vary among genetic stocks.

Beak-Trimming Effects on the Behavior and Weight Gain of Floor-Reared, Egg-Strain Pullets from Three Genetic Stocks During the Rearing Period ,

At 4 wk of age, White Leghorn pullets from three genetic stocks were divided equally into two groups for beak treatment. One group had half of the upper mandible and less of the lower mandible removed. For pullets in the other group, the beaks were kept intact. Chicks of the six combinations of stock and beak treatments were kept separately in two pens each. A sample of pullets from each of the 12 pens was marked, observed, and then weighed on Days 1, 7, 14, and 21 after beak-trimming and at 16 or 18 wk of age. The amount of feed consumed per pen was determined weekly from 4 to 7 wk.The stocks differed in terms of the percentage of time spent standing and crouching. The beak-trimmed pullets pecked less at the feed, delivered fewer pecks of all kinds, stood and crouched more, and showed more comfort activity than the birds with beaks intact. The pullets with the trimmed beaks gained 90% as much weight as intact-beak pullets during the first 3 wk after treatment and used 88% as much feed. During the 1st wk after the beak treatment, the relative weight gains and amount of feed consumed were even less for the beak-trimmed birds. However, by 18 wk of age, there was no difference in BW between the two groups of pullets.Interactions for beak treatment by age were found generally in both behavioral and performance traits. The initial differences between the beak-trimmed and intact-beak pullets tended to diminish with age. No differences were present at 16 or 18 wk of age, except for a continued lower frequency of litter-pecking by the beak-trimmed pullets.

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.

Research Note: Effects of Beak Trimming at Different Ages on the Body Weight and Feed Conversion of Guinea Fowl (Numida meleagris)

The effect of beak trimming at different ages on feed consumption and growth of meat-type guineas (Numida meleagris) up to 12 wk of age was investigated. In the first experiment, beaks of birds were trimmed at 7, 28, 49, and 70 days, respectively. In the second experiment, beak trimming was done at 42, 49, 56, and 63 days, respectively. Body weight, feed consumption, and mortality were measured first at 4 wk and weekly thereafter in both experiments.Beak trimming of keets at 7 days, significantly (P<.05) reduced body weights at 4, 8, and 12 wk whereas beak trimming at 70 days significantly (P<.05) reduced body weights at 12 wk. Beak trimming at other ages did not produce significant differences in body weights or feed conversions. Mortality was low (2 to 4%) throughout.

Effects of beak trimming and restraint on heart rate, food intake, body weight and egg production in hens.

1. Heart rate (measured on restrained hens in two experiments) was used as an indicator of short term fear and pain responses of light and heavy strains of hens subjected to beak trimming. 2. In the first experiment 3 mm of the upper and lower mandibles was trimmed, while in the second 0, 2, 4, 6 and 8 mm of upper and lower mandibles were removed. 3. Production responses to beak trimming were measured after trimming, for 4 weeks in experiment 1 and for 10 weeks in experiment 2. 4. In the first experiment the recovery of beak trimmed hens to normal heart rate took significantly longer than that of control hens subjected only to catching and restraint, suggesting that there was short term pain associated with beak trimming. 5. The heavier strain took about 4 min longer to return to a normal heart rate than the lighter strain, indicating a strain difference in responsiveness to beak trimming. 6. Trimming the hens' beak by 3 mm had no significant effect on rate of lay or body weight, but their mean egg weight was depressed and food intake took 9 to 10 d to recover to pre-trimming values. 7. In the second experiment a plateau was reached in recovery time of the heart rate once 4 mm of beak was removed. Removal of 4, 6 and 8 mm of beak depressed normal feeding and resulted in variable effects on production and body weight.