Short communication
Note on a method for individual recognition in
feed pecking in free running groups of hens
Eva BraÈnnaÈs
a,*, Bo-SoÈren Wiklund
a, Christine Burel
b,
Paul Ciszuk
b, Lars-Erik Liljedahl
b, Anders Kiessling
caDepartment of Aquaculture, Swedish University of Agricultural Science, S-90183 UmeaÊ, Sweden bDeptartment of Animal Nutrition and Management, Swedish University of Agricultural Science,
KungsaÈngen Research Centre, S-75323 Uppsala, Sweden
cMatre Aquaculture Research Station, Institute of Marin Research, N-5198 Matredal, Norway
Received 8 October 1999; received in revised form 7 March 2000; accepted 6 July 2000
Abstract
A system for automatic registration and individual recognition of feed pecking (activity and quantity) in groups of free running hens was tested. A PIT (Passive Integrated Transponder)-tag system was used to separate and register individuals when they were feeding. An electronic balance system placed under the feeder registered the amount eaten by each individual on a PC. A test with two different feed stuffs; oat and wheat was performed on three hens during a total of 6 weeks. #2001 Elsevier Science B.V. All rights reserved.
Keywords: Hens feed pecking; Automatic-feed registration; PIT-tag technique
1. Introduction
Studying the feeding activity in hens is interesting for several reasons. For example, to study feed choice in free running groups of hens fed with a split diet consisting of oat, wheat, bone meal, etc. and their ability to balance the nutritional requirements (Ciszuk et al., 1998). By recording a reduction in the amount of different feed stuffs at set occasions, the preference for different feed stuffs can be measured as a mean value for large groups of free running hens (Emmans, 1991; Ciszuk et al., 1998). Also, continuous registrations of feed intake are possible to achieve by placing computer connected balances under the
*Corresponding author. Tel.:46-907867681; fax:46-90123729.
E-mail address: [email protected] (E. BraÈnnaÈs).
feeders (You et al., 1997). However, important information on the individual variation in the ability to balance a split diet and whether it is effected by a dominant hierarchy in groups of hens is still not available.
An automatic device that registers individual feeding activity in groups of ®sh, have been successfully tested and applied by using a PIT-tag system in combination with self feeders (BraÈnnaÈs and AlanaÈraÈ, 1993). The aim of this work was to test the application of a corresponding PIT-tag system for individual recognition of feeding activity in groups of hens in combination with a computer-connected electronic balance placed under the feeder to register the reduction in feed stuff.
2. Material and methods
The feeder was made from a combination of a ®sh feeder (Sterner AB) and a pluming Y-tube (20 cm) with an inner rubber collar that reduced the spill when the hens pecked (Fig. 1). A standard balance (Mettler Toledo PB 8001, range 0±8000 g, accuracy 0.1 g) with a computer connection was placed under the feeder. A plywood box covered the feeder and the balance. The aim was to prevent the hens from sitting on the box which caused a disturbance of the balance. The box had an opening in the front that matched the opening of the feeder but without physical contact. An external PIT-tag antenna was placed on the plywood box at the feeder opening. The size of the antenna opening was reduced by two plastic stripes to prevent more than one hen eating at the same time. The PIT-tag registration system (Trovan LID 655 Decoder, Electronic Identi®cation Systems) consists of an antenna (loop assembly), a combined exciter and a reader board (placed inside the
covering box). The antenna was made of 40 loops of a thin copper wire coiled around a 50 mm long tube of PVC, with a diameter of 120 mm. The optimal angle for reading the tag was 90 or 1808and the antenna was placed vertically at the opening of the feeder. A PIT-tag, which comes close to the antenna (when the hens stick their heads in to feed), will be activated, sending a unique 10-digit hexadecimal code to the reader board. When a hen is pecking, the balance reacts to the weight change, a series of recordings will be sent as unstable data followed by a stable value when the feeder stops moving as the hen stops pecking. Signals from both the feeder and balance are transferred to a four serial ports multiport board (Moxa C 104) placed in a computer where the data was stored after giving a code by origin and exact time. Software was designed in Turbo Pascal to receive data and in Excel to extract the weight changes of the feeder in combination with the ID-codes. Data was obtained for the type and amount of feed stuff, the exact time of day and the duration of pecking session.
Three privately owned brown 1-year-old hens were used to test the system. The hens were ID-tagged subcutaneously in their necks by a veterinarian (with Trovan PIT-tags). A temporary hen house (1:2 m2:0 m, height 1.5 m) was built, using a children's playhouse combined with an outdoor fenced chicken-run (10 m2). The ¯oor was covered with shavings and hay. Two types of seed were tested separately, oats and wheat. The purpose was only to test the technical accuracy of the system and not the total amount each hen ate. The hens were also given additional feed such as worms, corn, shells, etc. to balance their nutritional requirements.
The system was tested in July±August 1998, starting with oats during 4 weeks and continuing with wheat during an additional 2 weeks. The hens and feeders were checked daily and the balance was tarred, starting with 0 g, every morning by automatically resetting the computer.
3. Results
Table 1
A section from a raw-data input file giving date, time, signals from the balance (S1) of present weight with stable values (S) and unstable values (D) of the feed and signals from the PIT-tag antennae (S2) giving the ID-code of the feed pecking hens
08/03/1998 13:18:02 S S 0 S1
08/03/1998 13:34:43 000142A54E S2
08/03/1998 13:34:44 S D 1.1 S1
08/03/1998 13:34:44 000142A54E S2 08/03/1998 13:34:45 000142A54E S2
08/03/1998 13:34:47 S S ÿ0.1 S1
08/03/1998 13:34:51 000142A54E S2
08/03/1998 13:34:51 S D 1.8 S1
08/03/1998 13:34:52 000142A54E S2
08/03/1998 13:34:57 S S ÿ0.3 S1
08/03/1998 13:35:02 000142A54E S2
08/03/1998 13:35:03 S D 0.8 S1
08/03/1998 13:35:03 000142A54E S2 08/03/1998 13:35:04 000142A54E S2
Table 2
Three hens intake of oat and wheat during 4 and 2 weeks, respectively
Name and ID-code
Total number of peckings
4. Discussion
Automatic registration using transponder technique in combination with an electronic computer-connected balance gives accurate information about the amount of feed stuff pecked from the feeder by individual hens in free-running groups. By using two or more systems, preference for different foodstuffs such as the ability to combine a full diet out of basic mixed foodstuffs can be recorded on individual hens in free running groups. The accuracy of the weight registrations of each mouthful can be improved further from 0.1 to 0.01 g by increasing the sensitivity of the balance (You et al., 1997). However, a stable indoor environment is then required to avoid too many disturbances. The tagging of the hens was successful and the reading accuracy was good during the test periods. Provided the tag is injected at right angle in the neck and that the antenna is placed in such a way that the hen must stick its head through to peck the grains, the PIT-tag reading are very reliable. By checking the raw ®le, bad PIT-tag reading is easily detected if sequential registrations with reduced total weight appear without PIT-tag registrations.
In conclusion, it is possible to automatically register when, what and how much each hen eats by using this type of system. The collected data can be correlated to growth performance of young animals or egg laying performance in hens. In this respect, we are developing an egg laying counting system, using PIT-tags, in order to measure the individual laying performance in groups of hens and to relate it to the feed choice.
Acknowledgements
We thank Kurt BraÈnnaÈs and Assistant Sune FaÈlt for building the hens facility, Torsten Eriksson for making the macro and Veterinarian Lars GoÈransson for PIT tagging the hens. This work was ®nanced by the Swedish Forestry and Agricultural Research Council.
References
BraÈnnaÈs, E., AlanaÈraÈ, A., 1993. Monitoring the feeding activity of individual fish with a demand feeding system. J. Fish. Biol. 42, 209±215.
Ciszuk, P., Charpentier, L., Hult, E., 1998. Free choice of feed for ecological hens. Fakta Jordbruk, No. 7. Swedish University of Agricultural Sciences, Uppsala, p. 4.
Emmans, G.C., 1991. Diet selection by animals: theory and experimental design. Proc. Nutr. Soc. 50, 59±64. You, T., VilarinÄo, M., Faure, J.M., Picard, M., 1997. Feed peckings in young chickens: new techniques of
