Cornish X on 18% feed from start to finish - the results

[Birdinhand]

I’m all ears but to say he was wrong will take some convincing as the solution he recommended lead to an immediate cure. The day I switched to a standard broiler formula all the issues ceased and the birds recovered most of their weight.

 

[U_Stormcrow]

I’m all ears but to say he was wrong will take some convincing as the solution he recommended lead to an immediate cure. The day I switched to a standard broiler formula all the issues ceased and the birds recovered most of their weight.

No worries - I'm up to the task. Its a pretty obvious error he made, and once I've explained, you will have a better grounding in amino acids, and be able to educate him.

Case of right solution/wrong reason why it works.

 

[U_Stormcrow]

The owner of the hatchery where I got them said this when I sent pictures:
“layer feed is too low in protein for Cornish Cross, and does not contain the proper amino acid profile which Cornish need to grow properly.

This part is true. For Cx to do well, they need both a relatively high Crude Protein level AND that Crude Protein needs to be balanced in a way containing adequate amounts of certain key amino acids. If it gets those, it can manufacture or synthesize the rest.

Cornish need 32 amino acids in order to thrive, and layer feed only has about 25, since layers don’t need a high protein diet, but do need extra calcium and sodium.

This part is wrong (at least, the second part, and partially, the third). There are 22 amino acids which make up all protein in a chicken. Of those 22, nine are characterized as "critical", "essential", or (more commonly), "limiting". They are called that because a chicken either can't produce that amino acid on its own, or can't produce enough of that amino acid to meet its daily dietary needs. Of the nine, the four most critical are Methionine, Lysine, Threonine, and Tryptophan. The first two appear on US feed bags, the second two do not - because its very difficult to miss the targets for those two with the typical corn/soy ration most popular in the US if you get the first two right - and because if you don't get the first two right, it doesn't matter how much "extra" threonine or tryptophan your feed might contain (or any other AA), because your bird won't be able to use it effectively.

Yes, active layers need more calcium, much more calcium, than a hatchling or adolescent bird. No, they really don't need more sodium. They can benefit from a bit of extra phosphorus, but sodium needs are pretty consistent across all ages and purposes.

Back to amino acids. While some would dispute, Methionine is probably the most important of the limiting amino acids in a chicken's diet - not only is it hard to find in plant sources, but biochemically, Methionine works much like the engine in a train. All proteins start with methionine during formation, with other amino acids being assembled behind it until the completed protein is made. And just like the engine on a train, it can decouple and leave after making a train of individual amino acid "cars", and go start making another train. Thats why a chicken needs only about 40-50% as much digestible Methionine as Lysine - but without available Met, no proteins get made.

In terms of macro effects, Met is associated with connective tissues primarily - skin, tendons, the digestive tract. All really important things. Lysine comes next, associated with muscle development, particularly breast muscle - but of course the heart is all muscle.

As well, many of the critical amino acids can be used to produce less critical AAs, but the reverse is not true. Methionine, for instance, can be used to create Homocysteine, which can then be used to make the AA Cysteine - but there is no biological process in a chicken that can turn Cys back into Met - its a one way road.

Looking at a Cx, and looking at a typical commercial layer, its visually obvious that they are both "chickens", but "put together" different. If you were to surmise from that that they might have different dietary needs, you would be correct.

In order to support that very rapid growth, Cx eat a lot - and because their ability to digest in a given day is physically limited - they do best with relatively high protein, moderate energy feeds when they are very young, and can be transitioned to a lower overall protein higher total energy feed as they age (to promote fat development and add to market weight, primarily). You see that in the typical ration recommendations, such as those found here (p10) for a production broiler.

Now, if you compare the first source I linked with the second source I linked (and the NRCS is likely to update - and increase - their recommends for commercial layers next time around, based on new research, such as that found here), you can start looking at the particular amino acid profiles desired for various "types" of birds, such as "meatbirds" like the Cx and "layers" for which layer feed is ostenibly designed.

Its not a fair comparison, its not even close. Meatbird feed is designed to support high rates of growth with a nutrient dense ration, layer feed is designed to maintain a bird whose growth is essentially done. and the numbers show it.

Meatbird recommend (average):

Crude Protein: 20%
Digestible Lys: 1.1%
Digestible Met: 0.45%
Digestible Thre: 0.73%
Digestible Tryp: 0.20%
Calcium: 1.0%
mKE: 12.6 MJ/Kg

Layer recommend:
Crude Protein: 15%
Digestible Lys: 0.69%
Digestible Met: 0.30%
Digestible Thre: 0.47%
Digestible Tryp: 0.16%
Calcium 3.5%
mKE: 11.6 MJ/Kg

Now we have to speculate some. There are studies that show that - given the choice - a bird will eat till it meets its daily intake needs of energy (this ability to self regulate has been at least partially bred out of Cx, some will litterally eat themselves to death). Other studies show that - given the choice - a bird will eat till its crude protein needs are met (the same studies show that the birds tend to be pretty bad at eating till individual AA needs are met). But in this case, it doesn't matter, because there is no choice.

If a meaty eats layer feed until its energy needs are met, it needs to eat about 10% more food. that results in number of (roughly) .77, .33, .52, .18. 3.9. In other words, by meeting its energy needs, it only reached 70% of its Lys needs, 75% of its Met needs, 75% of its Thre needs, and about 90% of its Tryp needs, while taking in 4x the amount of calclium it needs. So its both starving itself with attendant stunted growth (the protein) while poisoning itself on excess calcium.

If we assume instead that the little eating machines ignore their actual energy needs (as they have, in part, been bred to do) and instead eat until they've met their dietary crude protein target, their feed intake of the the layer increases 33%, and the new numbers are 0.91, 0.4, 0.63, 0.21, 4.55 and 15,5 MJ.Kg. Still missed Lys by 20% (less developed breasts, lower total meat mass, slower growth, missed Met about 10% (visually, you'd never notice), missed Thre about 15% (weaker membranes, reduced immune function), and met the Tryp target. On the other hand, its take in 4.5x the calcium it needs (link above) and has exceeded its energy needs by more than 20% - some of that will be excreted as waste, some will be deposited as fat, quickly contributing to FLHS, another cause of sudden death in poultry.

That's the simple answer - reality is a bit more complex, as excess calcium inhibits digestion and absorption of various nutrients, reduced Met intake can impact feed efficiency, reduced Thre can play havoc with the metabolism, etc...

When Cornish are fed an inadequate ration, they can essentially starve on the ration which will cause runting, stunting, poor growth and performance, as well as losses.”

True of everything, no different than sailors getting scurvy on long sea voyages w/o vitamin C or "mal de caribou" (literally, "caribou sickness", colloquially, "protein poisoning"), which comes of eating a diet of almost solely lean protein, such as rabbit or caribou...

See above. Layer is inadeqate for feeding Meaties not because its missing certain amino acids entirely, but rather because it has lower levels of crude protein generally, and because the amino acid profile of that crude protein is differently balanced.

Perhaps you found a feed with all 32 amino acids, or maybe being grass fed helped somehow. Your outcome was much better than mine. I’ve concluded that having them sit from being so heavy in the last week or so is simply a cost of such a meat productive bird.

Yeah, grass isn't a good protein source (I used Dehydrated, because this is a reputable source - adding water back in, fresh grass, just adds water. Ultimately less nutritious per pound consumed), and is typically quite low in the most critical AAs, Met and Lys.

Anyhow, hope that helps, that you now have a better understanding of the differences in feeds and the importance of at least a couple key AAs, and of course I hope you find it at least a little bit convincing???

 

[Birdinhand]

This part is true. For Cx to do well, they need both a relatively high Crude Protein level AND that Crude Protein needs to be balanced in a way containing adequate amounts of certain key amino acids. If it gets those, it can manufacture or synthesize the …

Anyhow, hope that helps, that you now have a better understanding of the differences in feeds and the importance of at least a couple key AAs, and of course I hope you find it at least a little bit convincing???

thank you for that, deep bow! If you have a chance, can you please cut and paste that into my thread called “trials and tribulations of suburban meat bird production”? I would like to have it to come back to and study. Do you have any suggested reading that goes into this level of detail? You might really enjoy the book, the behavioral biology of chickens, it’s specific to behavior but fun for folks with a science background.

 

[U_Stormcrow]

thank you for that, deep bow! If you have a chance, can you please cut and paste that into my thread called “trials and tribulations of suburban meat bird production”? I would like to have it to come back to and study. Do you have any suggested reading that goes into this level of detail? You might really enjoy the book, the behavioral biology of chickens, it’s specific to behavior but fun for folks with a science background.

Honestly, I learned most of what I know in a couple weekends worth of readings here on BYC. Someone more knowledgeable than I wrote some things, and linked some studies. SO I read them. Then I read the studies they referenced. and the studies they referenced... and some free online books were shared, and... You get the idea.

After that, people have asked me questions I didn't know the answer to, and when I had time, I researched and expanded my knowledge a bit more. There's an old thread at the top of one of the forum that links to a ton of older, but free, resources. Makes a great starting point.

and yes, I can link back. I'm good at linking. Don't consider myself an expert, so I try and link sources when I have time.

 

[cmobley]

First, thank you for doing this.

Second, if you get the itch, I'm curious what results would be if you used the same hatchery each time (my only batch where Hoovers via TSC and I was not impressed).

Hope to see more records like this in the future.

I second the not impressed part so far with Hoovers and tractor supply. Cheaper is not always better I just picked up a 80 bird order and 50 were dead. Yes they said they’ll refund for the 50 but this was my big jump into trying to process to sale. What a motivation killer.

 

[HenriettaPizzaNolan]

I second the not impressed part so far with Hoovers and tractor supply. Cheaper is not always better I just picked up a 80 bird order and 50 were dead. Yes they said they’ll refund for the 50 but this was my big jump into trying to process to sale. What a motivation killer.

Sorry to hear! That's a lot of dead birds. Yeah, I definitely don't think they have the highest quality birds, nor do they seem to give them the best care. That's what really makes me wonder how much the size difference in my 2 batches of CX was due to the different feed, or due to being from Hoover vs. Meyer. I'm sure it was a little of both.

 

[cmobley]

Sorry to hear! That's a lot of dead birds. Yeah, I definitely don't think they have the highest quality birds, nor do they seem to give them the best care. That's what really makes me wonder how much the size difference in my 2 batches of CX was due to the different feed, or due to being from Hoover vs. Meyer. I'm sure it was a little of both.

My batch of Cornish from Meyer last fall at 8 weeks on 18% feed all averaged 4 -4.5 lbs out of 25 birds only 3 were 5 lbs none made 6lbs. I’m using a higher protein feed from my co op on these that lived it’s 27% 16.00 a bag verses tractor supply’s purina at 26.00 a bag.

 

[HenriettaPizzaNolan]

My batch of Cornish from Meyer last fall at 8 weeks on 18% feed all averaged 4 -4.5 lbs out of 25 birds only 3 were 5 lbs none made 6lbs. I’m using a higher protein feed from my co op on these that lived it’s 27% 16.00 a bag verses tractor supply’s purina at 26.00 a bag.

You did 18% all the way from start to finish on that batch of Meyer chicks?

 

[cmobley]

You did 18% all the way from start to finish on that batch of Meyer chicks?

Yes it’s 14.00 a bag at my co op.