Tetrapod Zoology

Captive pheasants Phasianus colchicus frequently practise cannibalism: this isn’t necessarily as gruesome as it sounds, but mostly consists of repetitive pecking or picking that opens wounds or results in the removal of toes. In chicks, toe and beak picking are common, while vent, wing and head picking more frequently occurs in older birds. Open, bleeding wounds (when visible) cause the birds to attack again, and they will keep attacking until the victim is fatally injured or killed. All gamebirds practise this sort of behaviour in captivity, but pheasants are by far the worst.

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‘Outbreaks’ of cannibalism have been reported when young pheasants have been kept in over-crowded conditions. Boredom might contribute to the habit as much as over-crowding, so the best way of reducing its incidence is to give the birds stuff to do. Providing them with perches, lots of material to peck at (like hanging bales of straw, or naturally growing vegetation), and lots of space all helps to reduce the problem. It can be symptomatic of over-heating, so ventilation and temperature control need to be looked at when it occurs. But a few more solutions to the problem have been invented. Some are more objectionable than others. I’m not going to provide any moral perspective here; I’m merely giving you the information.

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The least extreme methods involve fitting the birds with structures – rings (like that shown above) or blinders or ‘spectacles’ – that stop them pecking. Rings fit under the palate, over the tongue, and insert into both nostrils. The ring is not complete, and if fitted properly it doesn’t damage any of the bird’s soft tissues. It also shouldn’t hurt the bird, but it does prevent it from closing its jaws, and thereby stops it from forming a point that can be used to peck with. Different sized rings are available for chicks and adults. ‘Spectacles’ and blinders are a bit more complicated, more difficult to fit, and more of an obstacle to the bird’s behaviour and well-being (they sometimes snag on feeders and other structures). They fit on to the dorsal surface of the bill, sometimes attaching to the nostrils. A selection of blinders are shown here [from Ernst et al. (2007)].

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By far the most extreme technique used in poultry management is beak trimming. The name makes it sounds less extreme that it is: it doesn’t involve shaving a few millimetres of keratin off the bill. Rather, about a third of the upper mandible is broken off. This can be done manually (with clippers of some sort; even nail clippers), or automatically with a machine like that shown here [image from here]. Because the beak tissue does grow back pretty quickly (like everything else in birds) trimming has to be repeated every 4-6 weeks. Lack of wear from an upper jaw tip sometimes leads the lower jaw tip to become over-long, so it has to be trimmed as well sometimes. I say that beak-trimming is ‘extreme’, but I think it’s practised pretty frequently in the poultry-rearing industry.

Quite why I got distracted by the world of pheasant cannibalism and management I’m not entirely sure, but I hope you found this interesting.

Ref – -

Ernst, R. A., Woodard, A. E. & Vohra, P. 2007. Raising game birds. ANR Publication 8155. University of California, Agricultural and Natural Resources (Oakland) [free pdf here].

Comments

  1. #1 Pete Buchholz
    March 19, 2010

    Are the premaxillae and dentaries cut in beak trimming, or is it strictly trimming of the rhamphotheca?

  2. #2 dmaas
    March 19, 2010

    Darren, you’ve progressed to bird fashion. And you manage to make even that fascinating. You deserve a beer.

  3. #3 Darren Naish
    March 19, 2010

    It’s all those Lady GaGa videos I’ve been watching. Pete: yes, the bones are ‘trimmed’ too, sometimes drastically. Nice.

  4. #4 Greg Laden
    March 19, 2010

    I wonder if getting chickens to NOT do this was part of the early domestication process of that particular “game” bird.

  5. #5 vespera
    March 19, 2010

    But chickens DO do that.

  6. #6 Sordes
    March 19, 2010

    Wow,I have never heard before about such rings, only about beak-cutting. Perhaps you could anytime make a blog post about animal mutilation for “human purpose”. I was really shocked when I read for the first time about “mulesing” (actually I was looking for information about merino sheep, because they have such cool horns). This procedure is really horrible. If I think about all the things humans do to make their pets or lifestock more profitable or nicer…docking tails, cropping ears, horns sewn or burned off, castrations…and nearly always without any forms of anaesthesia.

  7. #7 AnJaCo
    March 19, 2010

    Greg, vespera is right and commercially raised chickens are frequently beak-trimmed too. I don’t know if they are less prone to pecking than pheasants generally. As Darren points out, it is mostly a problem of birds kept in high density conditions. They don’t call it a Peck Order for nothin’!

    I raised and bred chickens on a rural farm for a few years. Completely free-range conditions. They could come and go anywhere at all times. Pecking was never a real problem. Only when the ruling rooster had had enough of a new young growing rooster did pecking cause any damage. After getting the opponent down he would kill the potential rival by pecking/hammering on the the back of the skull. Which meant chicken dinner for me.

    An interesting aspect of the use of pecking in the enforcement of the Peck Order is that the pecking is directed at the eyes. This is why when one handles birds it is important to keep the bird out of striking range of your eyes. I made that mistake [once] with one of my chickens and the result was one eye with blurry vision and continuous watering for three days. Curiously, I never saw any eye damage in any of my birds, ever. I think it says something about the speed of reflex reactions of the peckees. Selection has probably been working on that character for some time now.

  8. #8 retrieverman
    March 19, 2010

    We call these things peepers.

    Every pheasant I’ve purchased has had these things on them.

    It looks very strange when you come onto a pheasant farm and see scores of hens and cocks with these things on their beaks.

  9. #9 AnJaCo
    March 19, 2010

    Oh, and chickens eat their dead.

  10. #10 neil
    March 19, 2010

    @GregLaden I doubt it was much of an issue until the advent of industrial agriculture.

    Boredom induced chewing seems to be a pretty universal habit among tetrapods, pig’s tails are docked for much the same reason, and I suppose it could partly explain human habits like chewing gum, pencils, fingernails. Fish in crowded aquaria tend to be pretty chewed up too, but I’m not sure if that’s boredom related or just opportunistic feeders at work.

    What’s going on here? Is there some neurological explanation for the prevalence of this behavior?

  11. #11 Oll Lewis
    March 19, 2010

    Thankfully beak trimming is not a practice undertaken by the place I got my Reeves pheasant from. I was actually rather impressed by the conditions at the game farm I got him from. Lots of big enclosures, feeding and water stations, decent shelters and no over crowding, a good example of the correct way to rear game birds. Get the enclosure size and population levels right and you shouldn’t have to use blinders rings or trimming. Produces healthier birds too.

  12. #12 Rory
    March 19, 2010

    I agree boredom is a greatly contributing factor but I wonder if social structure has a bigger part to play in birds. One of our chickens became broody so we made her a surrogate mother using fertile eggs from a friend.
    We introduced the chicks once they were 9 weeks old and were horrified that once they ventured into the main group two were killed in a matter of days from each other(the third only survived by flying up on top of the chicken house)and the first was even attacked by mum. The problem arose because the youngsters would just run away from the adults, whereas the adults would submit to the pecking of the more dominant ones. Therefore the young had no social standing in the group and were eliminated perhaps as enemy birds.
    In a captive situation similar events could play out because there are so many individuals that it would be impossible to set up a social heirarchy and for each to remember the others social place. Therefore pecking would be continuus as no bird would continue to be challenged.

    By the way ex-battery hens are particularly aggressive. Could this be because of the cnditions they were brought up in?

  13. #13 HP
    March 19, 2010

    The thought occurred to me as I read this that perhaps you could use operant conditioning to give the pheasants some kind of harmless “ritual” behavior to do instead of pecking — basically, give them pheasant religion to save them from pheasant sin.

  14. #14 Chris M.
    March 19, 2010

    @HP: You’re talking about some serious investment of time and energy in birds that won’t be around long enough to learn the lessons effectively, and which could with much fewer resources be changed by improved housing conditions.

    Yes, this is extremely common in commercial chicken operations also; they usually just do the beak trimming, rather than the blinders or anything.

    @Greg, it’s actually in progress right now; definitely not part of the initial phase! Breeding for less aggressive chickens, you can have the high population densities without the aggressive consequences, and leaving an intact beak also decreases the amount of pesticide needed to control mite and lice populations on the birds. Intact beaks allow them to groom properly. It’s looking like a possibility, still only a few non-aggressive breeds.

    @Rory, the birds are housed in relatively small groups in a single cage, less than ten. Shouldn’t take too long to establish a pecking order there; constant interaction between the top and bottom of the order due to the inability to leave immediate reach is probably more important.

  15. #15 Noni Mausa
    March 19, 2010

    I never heard of the nose-rings — goth pheasants!

    A word about tail docking. I have seen it done and done it myself and really, it’s not a big deal. The pups are done at 3 days old when the tail bones are still soft as macaroni. You push the skin down towards the body, to retain extra skin which closes over the tail-end. A single snip yields a single yip and minimal bleeding. Dab on a bit of antibiotic powder and pop them back in with their mother, job done. “Dew claws,” those thumblike toes partway up the wrist, are removed in much the same way, but I have never snipped them so I can’t report if that’s easy or not. But it’s done at the same age, so I assume so.

    On the other hand, ear cropping is much more problematic. Not only must it be done when the pup is older (3-5 months) but it requires anaesthetic and an element of artistry on the vet’s part. Both ears need to be a good length and shape, and need to match, and there’s a few weeks of fussy aftercare to get the ears to stand.

    I am lucky these days, keeping a breed born with little nubbin tails and upright little-brown-bat ears, and needing no outside alteration fore or aft.

  16. #16 Cale
    March 20, 2010

    It’s a bit unrelated, but my pet starling requires beak trimming sometimes. First time I had to cut back an overbite, I was dreading it, thinking it’d be messy and painful, with blood, struggling, and alot of pain, (and with a small songbird struggling, the potential for injury to the bird is always there,) but all I had to do was cover his eyes with my fingers and nip the tip off with nail clippers as fast as possible… not even a drop of blood, and the bird seemed completely unaffected.

    Of course, he has no cagemates to be aggressive with, which is lucky, because even a tame starling has a bit of an aggressive streak.

  17. #17 Rory
    March 20, 2010

    @Chris M Yes I agree with that in a battery situation, but I meant in terms of farming for meat in big crowded barns or even free range as ours are.

    Or perhaps our hens are just particularly agressive. Having lived in small cages agression would have been an advantage to their survival.

    Isn’t there some act in place now in the EU which affords battery hens more space per hen and perches as a minimal requirement?

  18. #18 Andreas Johansson
    March 20, 2010

    The jawbones grow back after “trimming”? Or just the keratin?

  19. #19 Christopher Taylor
    March 20, 2010

    I was really shocked when I read for the first time about “mulesing” (actually I was looking for information about merino sheep, because they have such cool horns). This procedure is really horrible.

    Mulesing is pretty horrific, I’ll agree. Unfortunately, so is flyblow (what mulesing is supposed to add extra protection against), probably even more so. I’ve had the misfortune of seeing flyblown sheep – it’s a memory that sticks with you.

  20. #20 retrieverman
    March 20, 2010

    The chickens that usually get their beak clipped are usually laying hens in battery cages. They wind up depleting the calcium in their bones from laying so many eggs that they go and attack their cage mates to replenish their stores.

  21. #21 Jerzy
    March 20, 2010

    Bleee… disgusting.

    Rearing pheasant for mass release for shooting is generally disgusting. Over 90% of these pheasants die within few weeks, because they don’t know how to feed in the wild. Now I see that before release it is no better.

    About bloodthirsty Galliformes – pheasants and junglefowl eat carrion. They were also observed cleaning wounds of injured wild buffalo (Water or Gaur). Buffalo laid down to let the birds help him.

  22. #22 Nick Gardner
    March 21, 2010

    @neil re: fish and biting

    I think it’s mostly aggressive behavior done by fish looking to maintain their sense of space from my experience with fish. Not all fish engage in this behavior, only some. I had a tank full of at least 20 mollies, and they never attacked each other. Other fish, like tiger barbs, are much more aggressive though.

  23. #23 Jim Thomerson
    March 21, 2010

    We raised a bunch of pheasants one time and didn’t have any problems. Mother would give me 25 cents for each armadillo I killed (dug up her garden). We would skin and shell them and hang them on the fence of the chicken yard. Chickens would skeletonize them pretty quick.

  24. #24 David
    March 21, 2010

    This gets more interesting all the time. To prevent cannibalism in pheasants, all you need is a dead armadillo. I’m not sure where to find them here in London, Then again, I haven’t noticed too many pheasants around these parts either.

  25. #25 retrieverman
    March 22, 2010

    During the Great Depression (the one in the 30′s), people would often kill armadillos as a food source. The animals were called “Hoover Hogs,” not because they were of any use as vacuum cleaners, but because the president at the beginning of the Great Depression was named Hoover.

    Nine-banded armadillos are going to be found in almost all of the US. Their range continues to expand. They could even be found in New York.

  26. #26 Darren Naish
    March 22, 2010

    For more on the spread of armadillos across the US, go here and look at point 2.

  27. #27 retrieverman
    March 22, 2010

    This is a projection of nine-banded armadillo range in the US:

    https://www.msu.edu/~nixonjos/armadillo/pics/d_novemcinctus_estimated_range.png

  28. #28 Jim Thomerson
    March 22, 2010

    Armadillo does, in fact, taste like chicken; so, perhaps our chickens thought they were doing canabalism! I’ve been told of a pet armadillo who lived under a dresser in a trailer. It was hairy all over. Seems the hairs wear off in the burrow.

  29. #29 Finback
    March 25, 2010

    Hm. I have seen a cassowary in a zoo here with half of the upper mandible missing; I queried a docent if it was due to a disease of some kind, eg a cancer, or from some violent incident. Sadly, these docents didn’t know (nor did they know cassowaries even live in Australia), so I never got a good answer. It seemed too rough in recollection, but.. perhaps it was done to minimise pecking behaviour? I did contact the zoo directly to ask, but never received a response..

  30. #30 keith
    April 1, 2010

    red contact lenses for roosters prevented pecking assualts, why i don’t know

  31. #31 freepoultryconsultant
    June 4, 2010

    A lot of things come into play when it comes to causes of cannibalism. Three of the more common causes are 1. breed defect caused by primary breeders in pursuit of “better breed”, 2. nutrition inadequacy like salt level in feed, and 3. mismanagement. I have posted an article on Controlling Cannibalism in my blog freepoultryconsultant.blogspot.com and I hope I have contributed a little on this topic. I have managed a gamebird farm and for me, being attentive to the needs of your pheasants and developing a keen eye before cannibalistic behaviour develops is critical in controlling cannibalism.

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