A visit from the vet about our chickens

We currently have approximately 83 hens of various types and ages along with two roosters.  Our flock was recently infected with scaly-leg mite.  We had been treating with a combination of pyrethrin, warm water baths, and Vaseline application to their legs.  Additionally, we have been noticing rather low egg production levels: sometimes as few as 6 to 15 eggs per day during the month of November.  While we expected production to dip with colder weather, getting as few as 6 eggs per day from an 80 chicken flock is not encouraging especially when they are eating through around 25 pounds of feed a day or more at a cost of $7-8 per day.


Veterinarian Dr. Robert Krueger (aka Dr. Rob) of the Mount Vernon Animal Hospital visited the farm on 11-29-2016 came out to evaluate our chicken flock.

First and foremost, Dr. Rob said that the age of our flock was the key contributor to overall poor flock health, low egg production, and high cost of maintenance (both for treatment and feed). While industrial producers cull hens at the age of 12 to 16 months in general, he said that heritage birds not under as much production pressure could live up to 2 years of age, but probably not much longer than that.  There are several benefits to early culling, principally, an overall healthier flock with a better collective immune system and much better egg production.  A side benefit is that culling of chickens while they are still healthy and relatively young is that you can enjoy the meat.  In other words, they feed twice.  Old chicken’s meat is tough, undesirable, and when recently medicated, unusable which means there is unnecessary waste occurring.

Roosters are fairly similar.  They reach the height of their reproductive capabilities around a little less than a year.  After two years, they’re ability to fertilizer eggs diminishes exponentially.  While rooster over two years of age might be still good for protecting the flock they are not good for maintaining by creating fertilized eggs for incubation.

In terms of the mites, Dr. Rob advised that pyrethrin and pyrethroids are not very effective at killing mites and generally waste of money and time.

Cycle of scaly-leg mites is 7-12 days meaning a new brood of mites are hatched from their eggs every week or so.  Many treatments including suffocation (e.g. application of Vaseline or mineral oil to legs), pyrethrins, and general insecticides such as Ivermectin do not kill eggs so multiple applications of chosen treatments should occur around every 7 to 10 days to kill newly hatched mites.

Dr. Rob said that Ivermectin is quite effective at killing various types of mites–in addition to being a general dewormer–and that it can be applied either orally (as drops) or injected.  He advised that injection is generally much easier. Ivermectin is very inexpensive for treating a small flock (labor is cost prohibitive in a commercial setting). Cost is about $0.10 per dose, but note that each bird requires 2-3 doses and the labor required for catching and treating birds makes it quite expensive apart from the actual cost of Ivermectin.

Mineral oil or castor oil in spray bottle recommended over use of Vaseline for ease of treatment.

Overall key recommendations from Dr. Rob:

  1. Decide What We Want to Be: We can either be a working farm that aims to maximize productivity while still practicing good animal husbandry and sustainability or we can be a “bird sanctuary”, but we can’t be both!  Introducing new birds into the existing flock that already has a heavy parasite load is not a good practice.
  2. Good record keeping: Knowing the age and past history of animals is critical to their care.  This includes banding chickens and recording production levels, illnesses, treatments, and so forth.
  3. Depopulate-Repopulate: The most effective way to control for scaly-leg mites and other pests and pathogens that might be in our flock is to cull the entire flock, re-locate the coop and start all over again either by incubating eggs from a healthy nearby flock or from purchasing hatchlings from a reputable source that can guarantee lineage and do routine testing for disease.
  4. Preventive Measures: Segregating flock from other wild and domestic birds (particularly in regard to avian influenza), better coop cleaning, use of diatomaceous earth in dust baths, and rotation of coop location.
  5. Put a ‘Culling Program’ in Place: Once we decide whether we want to be a production farm we need to come up with a systematic record keeping and culling program at which we cull the birds at a particular age.  Again, if this is done when the hens are fairly young (i.e. less than 2 years) the meat from the ‘stewing hens’ will be a nice secondary benefit instead of letting it go to waste

Other notes from the vet:

Older hens need more calcium–suffer from osteoporosis the same way humans do.  One sign of this is softened eggs which are more prone to toe pokes.

Double yolks are sign of over stimulation (either by light or by nutritionally dense food).

Dr. Rob recommended visiting a commercial barn.  Even if this isn’t the type of ‘mass production’ we want to model at the Kenyon Farm, it may still be a highly valuable learning experience from which we can gather better insight to better taking care of our flock.

Lighting of 12-14 hours will maximize production.  Inflorescent lights are acceptable (though LED preferable for energy conservation) and should be turned on from 6:30-9 am and again from 4:30 to 9 pm.  Lights should not be left on during the day as this may encourage hens to stay in the coop.

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