Poultry Questions Answered - February 2011
Written by Sue Clarke. Provided by New Zealand Lifestyle Block, incorporating Growing Today, magazine February 2011.
Question - What causes dermatitis?
I read in an old Growing Today (November, 2008) that parsnip, parsley and celery cause dermatitis on poultry, but I have not been able to find this information anywhere else. I was going to buy the Kings Seeds chicken greens mix until I noticed it has parsley in it. Do you know anything about this?
– Jason Harrow, New Plymouth
Sue's reply
The original information on parsnip, parsley and celery causing dermatitis was taken from NZ avian vet Neill Christensen's book "Healthy Free Range Hens". He gave me permission to use his findings, some of which he got from some old text books on poultry.
The details say that parsnip, parsley and celery all contain furocoumarins in their leaves and roots which can affect skin and cause phylodermatitis on bare skin.
I know that parsley and celery should not be fed to pigs either, as the blisters caused by the furocoumarins on the noses and mouths has been mistaken for false alarms of Foot and Mouth disease.
Neill Christensen's notes say that post mortem findings of dead birds that had ingested parsnip, parsley and celery showed dermatitis and vesicles (fluid-filled blisters).
I also found a reference from the Food Safety Hazard Book by Richard Lawley, Laurie Curtis and Judy Davis. If you can't find a copy, you can read the information on dermatitis by doing a search for "foods with furocoumarins" in Google Books.
Question - Greens for poultry
I don't think Sue has said anything about green feed for poultry. Silverbeet is a staple but there are other equivalent plants I understand. We especially grow 25 silverbeet plants for the six brown Shaver hens our son and his family have up at Te Hana. The hens LOVE IT!
– Ray Clarke, by email
Sue's reply
As you are probably aware, poultry are omnivores and enjoy a little bit of everything. Geese and ducks are far better adapted to eating more of their diet in the way of green leafy plants and grass than the chicken.
Greenery such as silverbeet, spinach, cabbages and, to a lesser extent, lettuce and grass, are relished by poultry as an addition to their diet but greens like these should not form a major part of their daily intake.
There are other crops hens may enjoy when in season like pumpkin, apples, weeds pulled out from the garden, dandelions, puha, chickeweed etc.
Green leaves and grass contribute fibre, vitamins (especially A & D), and minerals to the poultry diet. Quality will vary: young season growth is preferable, as coarse old grass and leaves are high in fibre and not much else. The fibre can cause problems because it is not readily digested so its value as even a carbohydrate is often poor due to its undigestability, and birds do not have the right gut enzymes and microflora to extract its basic nutrients.
Long fibrous material can also cause problems, binding in the crop or causing impaction in the gizzard.
The other contributions of greenery are xanthophyll and chlorophyll which are colouring agents for skin and egg yolks, but these do not have any other nutritional benefit.
Because a chicken needs to eat a diet which contains adequate protein for growth, maintenance and reproduction, it adjusts its intake to meet the protein demands. If protein in the diet is low it has to eat much more bulk in the search for protein so it over-consumes carbohydrate which can then be laid down as fat.
If large quantities of leaves and grass are available then it may fill up on these and not leave enough room for the more protein-rich parts of its diet. This is why it is better to feed a main diet - be it a commercial balanced feed, or a homemade mix containing grains plus protein (milk, meat meal, soya beans, peas) - first thing in the morning, before giving birds access to a free range area. The vege garden or some green leaves should be a top-up, not the main meal.
Your son's brown Shavers are high performance birds with reasonably small appetites so they really need a high quality diet to perform at their best. I keep trotting out a saying I heard from an avian vet regarding feeding today's hybrid poultry: "You can't run a Formula 1 racing car on diesel!"
By all means, offer the girls some daily greens as a treat and a top-up to their basic diet - and it will also help them occupy their day - but to help them produce eggs they need a diet which is at least 18% protein, preferably sourced from animal products such as meat or milk or a commercial layer pellet, crumble or mash designed for free range birds, and including calcium. Grains should make up 60% of the daily diet and the greenery probably 10-20%.
This article was provided by NZ Lifestyle Block, incorporating Growing Today magazine.
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