The dy­ing flock mys­tery

NZ Lifestyle Block - - Contents -

Iam of­ten ap­proached for help and ad­vice re­gard­ing poul­try prob­lems, and while I’ve been work­ing with poul­try, per­son­ally and in the in­dus­try, for 50+ years, I still find new cases in­valu­able, adding to my li­brary of ex­pe­ri­ence.

Ear­lier this year a friend called me, very wor­ried. Her young span­gled Ham­burg flock was dy­ing – five in just one week. Her hus­band thought they might have picked up sal­mo­nella from their ducks as they were all run­ning to­gether.

The flock in ques­tion was hatched by her from fer­tile eggs. She had raised 20 chicks to 12 weeks old, and had re­cently moved them off Chick Starter feed. They were now eat­ing with the older birds on the block, a mix of sev­eral va­ri­eties in­clud­ing up to 80 Hy­line lay­ing hens (in a sep­a­rate run) and some older light Sus­sex.

One of the mis­con­cep­tions for many back­yard free-range flock own­ers is they think their birds won’t get diseases like com­mer­cial flocks do, and that their birds only get worms or mites.

But noth­ing could be fur­ther from the truth. When birds in a com­mer­cial flock get sick, a spe­cial­ist health of­fi­cer and then an avian vet will be brought in quickly, op­tions will be as­sessed, tests will be car­ried out to con­firm the cause, and med­i­ca­tion will be pre­scribed. When a bird in a small flock gets sick, it al­most never gets this kind of care­ful di­ag­nos­tic as­sess­ment. An owner or a more ex­pe­ri­enced poul­try per­son (like me) or more rarely a vet may make an ed­u­cated guess as to the cause, but usu­ally the bird doesn’t see a pro­fes­sional or get treat­ment be­cause it’s not eco­nomic, and/or the owner chooses to try and man­age it on their own. I didn’t get to see these birds to as­sess their con­di­tion, but sud­den deaths in young birds re­cently hav­ing changed off med­i­cated feed meant the im­me­di­ate sus­pect was coc­cid­io­sis (see page 61). I ad­vised iso­la­tion (to pre­vent

and it’s ex­pen­sive: $50-$60 per 1000 dose bot­tle which must be care­fully stored and only lasts a very short time, ne­ces­si­tat­ing buy­ing more for ev­ery batch of chicks you hatch or new birds you in­tro­duce.

In the mean­time, after treat­ment with an­tibi­otics, there were no fur­ther deaths and the re­main­ing birds were only show­ing signs of the oc­ca­sional sneeze.

The de­ci­sion was made not to carry out blood tests on the rest of the flock or to ad­min­is­ter vac­cine (at an es­ti­mated cost of $400) as sug­gested by the vet, but to iso­late and maybe kill the en­tire span­gled Ham­burg flock (10 re­main­ing birds) to pro­tect the 80 lay­ing hens if their con­di­tion de­te­ri­o­rated again. Chances are the other birds in her flock had al­ready come into con­tact with the disease and be­come im­mune. In the mean­time, strict quar­an­tine and a clean-out of the young birds’ hous­ing was ad­vised.

Where the disease came from is a mys­tery. It’s most likely it was al­ready in the en­vi­ron­ment and the young birds and their im­ma­ture im­mune sys­tems were then ex­posed to it. ILT is not egg-trans­mit­ted, so it’s pos­si­ble it came in via wild birds car­ry­ing in­fected nest­ing ma­te­ri­als from an­other flock, or it was ac­ci­den­tally trans­ported in on the shoes or clothes of a vis­i­tor with in­fected birds at home.

Luck­ily it was prop­erly di­ag­nosed. If that test­ing hadn’t taken place, we would never have known the cause.

It’s a les­son to never take un­ex­plained deaths for granted, es­pe­cially when it in­volves more than 2-3 birds. Act­ing quickly, through a vet if pos­si­ble, could per­haps avert an ex­otic disease out­break too.

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