new research debunks trad views on nutrition

[Perris]

".. Food selection can be very precise: it has been shown that the fowl has specific appetites for such essential elements as calcium (Hughes and Wood-Gush, 1971a), phosphorus (Holcombe etal. 1976a) and zinc (Hughes and Dewar, 1971), for vitamins such as thiamine (Hughes and Wood-Gush, 1971b), and for protein (Holcombe et al. 1976b). The central thesis, that fowls possess an effective self-selection mechanism, is not in dispute. What is at issue is the control system underlying the selection, whether it applies to all theindividual components of adiet, and whether or not it offers apractical means of formulating diets for choice of feeding regimes with advantages over the feeding of complete diets. Choice feeding was a recognized method in the past (Winter and Funk, 195 l), before knowledge regarding formulation of complete diets had reached its present high standard...."

Source

Unfortunately, I can't access the entire paper. Later, I will try to sift through his sources and those listed as using thos paper for a source.

Edit to add
The source is

The principles underlying choice feeding behaviour in fowls—with special reference to production experiments​

BO Hughes
World's Poultry Science Journal 40 (2), 141-150, 1984

thank you; I'll try to find it now.

 

[Perris]

".. Food selection can be very precise: it has been shown that the fowl has specific appetites for such essential elements as calcium (Hughes and Wood-Gush, 1971a), phosphorus (Holcombe etal. 1976a) and zinc (Hughes and Dewar, 1971), for vitamins such as thiamine (Hughes and Wood-Gush, 1971b), and for protein (Holcombe et al. 1976b). The central thesis, that fowls possess an effective self-selection mechanism, is not in dispute. What is at issue is the control system underlying the selection, whether it applies to all theindividual components of adiet, and whether or not it offers apractical means of formulating diets for choice of feeding regimes with advantages over the feeding of complete diets. Choice feeding was a recognized method in the past (Winter and Funk, 195 l), before knowledge regarding formulation of complete diets had reached its present high standard...."

Source

Unfortunately, I can't access the entire paper. Later, I will try to sift through his sources and those listed as using thos paper for a source.

Edit to add
The source is

The principles underlying choice feeding behaviour in fowls—with special reference to production experiments​

BO Hughes
World's Poultry Science Journal 40 (2), 141-150, 1984

OK, I have it. I'll read and get back to you.

 

[NatJ]

when they are raised by a broody, foraging on grass and leaf litter from hatch, they are trained from day 1 what's good eating, and how generous the natural buffet is

proper experimental set-ups to test poultry's ability to choose a balanced diet always starts with sterile chicks, raised artificially, and usually given commercial feed for the first N days before the experiment starts. Those selected for the test group then have to discover it all themselves, as chicks (test subjects are usually killed on or before they are a couple of months old).

Real chicks raised by a broody have an adult to teach them what's good eating and what's not. And free ranging birds can eat anything they find. But that's too hard for the human experimenters to cope with - all those variables! non-sterile birds! the great outdoors! could eat anything!!! - so they stick with walking nuggets and a controlled environment. It's better than nothing, but it's not normal. Just because something can be measured, it does not mean it is correct, or better than something that can't be measured.

I wonder if experimenters could try an in-between version:
raise some number of chickens that get to choose (as they have done before), but when those are adults and some hens go broody, let them raise chicks with the same selection of foodstuffs. So they would only have the choices provided by the people, but the chicks would have adult guidance from the first day. One control group of chicks could be given the same choices but no guidance, and another control group of chicks could be given the formulated feed. That would at least help figure out how much difference the training (by a broody hen) makes.

I can see plenty of downsides, of course. The total time for the experiment would be much longer, they would have to use a breed that could go broody, there would probably be variance in how well different broodies do, and so forth. They could have relatively consistent chicks by giving each broody a clutch of eggs from the same source as the control chicks, or even by hatching all chicks in an incubator and giving some to each broody to raise. If the broodies came from a batch that self-selected foods and had varied results (like some of the studies show), it would be useful to know which broodies had grown bigger/faster, to see if they teach their chicks to select things that give the same growth pattern.

 

[3KillerBs]

I am looking forward with interest to see if fertility rates are better this year.

That will be interesting to know the results.

 

[Perris]

OK, I have it. I'll read and get back to you.

It is behind a paywall so linking is pointless and wholesale copying disallowed.
Fortunately there is a summary so it will have to do. Obviously if you have any specific query about any specific issue, ask and I'll go back through to see if it's addressed.

"The evidence is now strong that domestic fowls, like other animals, can select a diet which provides them with all the nutrients necessary for maintenance, growth and production. Theoretical models suggest that, compared to the feeding of a standard complete diet, there should be a gain in efficiency in a flock on a self-selection regime, because individuals at different levels of production can select diets appropriate to their requirements. Studies in which these relationships have been investigated have, however, yielded variable results. Egg production in layers or growth in broilers was generally similar in birds on self-selection regimes or on complete diets, but, depending on the study, food utilization efficiency was inferior, similar or superior for reasons which were not immediately clear. In broilers receiving a choice between two diets which varied in protein content there was some evidence that the lower level of protein intake was set by requirement, but that the upper level was set by the palatability of the higher-protein diet. In laying experiments, generally concerned with calcium selection, intake was usually well-matched to requirements, production was good and food intake was similar or, on occasion, lower. In both types of investigation it was clear that metabolic and nutritional requirements were not the only factors governing selection, and there were some experiments in which a self-selection regime yielded poor results. Behavioural responses concerned with the relative palatability of the diets offered, the learning rate and previous experience of the birds, social factors and even trough position may all affect the results of a study. The development of high-yielding hybrids has produced animals with demanding nutritional requirements, and insofar that nutritional regulation and control systems are inherited and there has been no genetic selection pressure to develop them, these control systems may not be adapted to meet requirements at the highest production levels."

 

[3KillerBs]

The development of high-yielding hybrids has produced animals with demanding nutritional requirements, and insofar that nutritional regulation and control systems are inherited and there has been no genetic selection pressure to develop them, these control systems may not be adapted to meet requirements at the highest production levels."

This is why I made my previous post in re: gamefowl/landrace birds vs. birds that have been selected for high production.

For many of us, these are simply not our great-grandmothers' chickens and, additionally, we're not living on great-grandma's diversified small farm.

 

[Perris]

This is why I made my previous post in re: gamefowl/landrace birds vs. birds that have been selected for high production.

For many of us, these are simply not our great-grandmothers' chickens and, additionally, we're not living on great-grandma's diversified small farm.

indeed.

And your point about natural selection was valid too; when my birds started free ranging, they had no teacher and they (and I) had to discover what worked for ourselves. They have got better at it each year. Last summer's zero loss to predation was a first; in previous years we've lost at least a couple of chicks to the hawks or foxes - with a clear favouring of light coloured males. I have noticed males are prone to wander further from the broody, and light coloured chicks are easier for predators to spot than better camouflaged chicks.

 

[Folly's place]

Here small cockerels of any color were taken by hawks more frequently. This winter for the first time we lost two white standard hens, and the first was seen taken by a Cooper's hawk, who was smaller than the hen!
Mary

 

[Shadrach]

I can recheck it later today, but I'm pretty sure I got that right.

Oh reading on a bit more, it looks like its been sorted it out!
I'll still check it though.
What do you think of this feed? Could it cause problems in the long run?
I'm not thinking of using it, but I just like to know of feeds that I could make, if I had to. (like in the past we have been stuck at home because of flooding)
Could the fish meal be swapped out for a different meat?

I don't know what fishmeal is like where you are but what I've found so far in the UK doesn't look like anything I would want to feed to the chickens.

 

[Sussex19]

I don't know what fishmeal is like where you are but what I've found so far in the UK doesn't look like anything I would want to feed to the chickens.

I don't even know if you can buy it here.
I have never seen it anyway
Thus why I was wondering if you could swap it out for something else.