Fair enough, but isn’t it good to have an open discussion?
This was the first resource Rooster recommend 11.5% protein .75% Calcium - I’m specifically asking about roosters here. Not laying hens which are vastly different. Right?
Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners, 2nd Edition
Cheryl B. Greenacre (Editor), Teresa Y. Morishita (Editor)
ISBN: 978-1-119-51175-5
July 2021
Wiley-Blackwell
Query. Honest one.
Why do you think that's a reliable source?
Yes, I get that Cheryl B Greenacre is at U of Tenn Knoxville
Yes, I get that she's published
a lot of papers.
Oddly, I'm not finding much on chickens. Actually, I'm finding no research by her on chickens. She's a generalist. Perhaps a very qualified generalist, but her research focus isn't nutrition.
Go back to the chapter you are relying on. Who is SHE citing for the basis of her opinion? Let's go back to the source.
and yes, the nutritional needs of breeding stock Roos for meatbird lines of Cx (i.e Cobb-Vantive 500s, Ross 308s, etc) are radically different thann most everything else because - as others have correctly pointed out above - they are deliberately starved to retard a rate of body growth genetically engineered to result in large, tender birds on dinner tables at very young age. That same engineering via selective breeding results in extremely low "natural" fertility, however. The same diet that powers that incredible growth rate is contrary to prolonged life or reasonably successful rates of reproduction.
The answer, btw, is that she is largely relying on research from Hocking in 1990 (Hocking, P. M., 1990. The relationships between dietary crude protein, body weight, and fertility in
naturally mated broiler breeder males. Br. Poult. Sci. 31:743-757.) and perhaps Siviera (Silviera, M. M., A. Freitas, C. Moraes, F. Gomes, F. Litz, J. Martins, N. Fagundes, and E. Fernandes, 2014.
Feeding management strategy for male broiler breeders and its effects on body weight, hatchability and fertility. Braz. J. Poult. Sci. 16:397-402) last decade. Because they are about the only studies out there not in the control of Cobb-Vantive, Ross, and the rest.
and they are specific to the highly genetically selected Cx class of birds, "broilers".
If you will forgive the anecdote, I've raised Cx. The only time they moved from the food was to get a drink. They were too fat, ungainly, uninterested, and slow to have any hope of successfully mating a more "normal" hen, even if they could mechanically make the correct contact. I ended up breeding a Cx hen via a "regular" rooster - she didn't have much choice, too ungainly to run away...
Conveniently, the above studies agree w/ my anecdote. Here's the money line from the second study:
The fertility of broiler breeder flocks declines during the last phase of their reproductive life (Creel et al., 1990; Walsh & Brake, 1997).
This is mainly due to the progressive reduction of mating efficiency and frequency (Duncan et al., 1990),
which has been attributed to excessive weight gain in males (Hocking, 1990; Hocking & Bernard, 2000).
I commend you for doing your reading, but its is very important to keep in mind the limits of the research. What is applicable to one situation is not necessarily applicable to all others.
and were you to make a study of the collective anecdotes of those of us feeding "conventional" barnyard mixes, dual purpose, and "heritage" breed roosters, a suspect the vast majority of us would report that our roosters respond to a relatively high CP "all flock"-type formulation feed by...
...eating less.
Cx, on the other hand, seem to have had the signal that tells their body that it's need have been met "turned off".
Hope that helps maybe a little?