Perch width, what’s the science?

[centrarchid]

Before going off mission in post above, my intent was to indicate that chickens I have observed roosting where they prefer typically roost on branches with diameters smaller than what most people consider for supporting chickens in a coop or building. Consider that with this experiment and how it is interpreted.

I have considered using smaller diameter roosting supports but have trouble making them strong enough to support groups of adult chickens that weigh much more than what a given branch in a tree must support. Another problem stabilizing the smaller diameter roosts as they have less material to work with as you build them into balance of coop / building. I have been sucking it up and buying larger pieces more do to construction issues than anything else.

 

[lazy gardener]

Re: birds roosting in a tree vs. in coop on a single perch: I'm guessing that the tree roost involves multiple branches. Thus, the weight of the flock is more evenly spread out. While in a coop, there may be 20 birds roosting on a single perch. Function alone demands that the linear roost in a coop must be greater in diameter to support the weight.

An other factor that enters into the equation: Location, location, location. My birds fight over the "window seats, as well as the corner seats.

I'm guessing that birds roosting in a tree tend to roost close to the trunk?????

The theory of a chicken being better able to cover her toes and protect from frost bite is a bit dubious. It's obvious that a chicken CAN cover her toes when sitting on a narrow perch. But, is there some insulation value provided when she is sitting on a wide surface??? I wonder if the issue re: winter frost bite resulting in loss of toes is more a function of overcrowding, which results in cold wet bedding, which results in cold wet feet.

 

[ShanasCastle]

I’ve often read that perches for chickens should be two inches wide or more.
Some people recommend four inches.
It’s also recommended that the perches should be flat.
When the chickens here go up a tree, they don’t choose to roost on the wide branches, they seem to prefer branches that they can curl their toes around; nothing like four inches wide and usually under two.
When chickens walk, they don’t bend their toes much.
When chickens scratch the ground they don’t bend their toes much either,
The chickens front toes have two joints and the back, a single joint. What are these joints for if not to grip a perch? Most of the actions I see chickens do with their feet don’t require the degree of articulation that they have available.
I’ve read that flat wide perches reduce the occurrences of bumble foot, but I thought bumble foot was caused by repeated high force impact sometimes received by jumping on perches placed too high, nothing to do with the perches width, or shape.
I’ve also read that wide perches help keep the chickens foot warm, but I get chickens who have sat on eggs with aggravated scaly mite because the feet don’t receive adequate ventilation and stay damp and warm.
So, why do people recommend wide perches? Is there any science behind these recommendations?

I’ve posted this in this section because if the recommendations are wrong and there is no science behind them then given time we’ll end up with flat footed chickens.

Okay way to go getting mu brain working in the morning!! Now I'm curious! I bought two identical prefab coops that have two roost bars but they were only an inch off the floor so we removed those and fixed them in the covered run. They are only a Max of 2" wide. I have two sizes of birds and this size seems to work well for both. Now I'm not sure if they are too small and will cause foot issues! Great post!

 

[pipdzipdnreadytogo]

'Digital tendon locking' actually does occur in the Galliformes, including Gallus gallus. It's not a specific trait to Passeriformes and their closer relatives. In fact, the same tendon locking mechanism is present in a wide variety of species from many of the avian orders, including those that do not normally perch, such as Mallards. So the Galliformes may have split off much earlier than other bird species, but this mechanism apparently developed before then.

Also, it goes far beyond just the bending of the leg causing the toes to grip. There are actually rough patches along the tendons that 'mesh' with one another to lock in place. This is the same across avian orders with the trait, not specific to any in particular, and occurs early in fetal development. We know it occurs in Gallus gallus through dissection of the foot revealing the presence of these rough tendon patches.

As for perch width, this is a commonly cited study about chicken perches which concludes that flatter perches are better for keel health, but rounder perches are better for foot health. From that, I would assume that a flat perch with rounded edges would be the most optimal overall--but that's just my inference from the data given and by no means actual, proven science. The birds themselves seem not to have a preference, other than that they seem not to like round perches with smaller diameters (ex. in the above article, a citation states that the birds preferred ~4-inch diameter round perches rather than ~1-inch diameter perches). Please note that birds in these studies are usually ones that had no access to perches before and were given the option, not ones who had experience with X size perch and were given the option of Y size perch. So, I would gather from this and from previous posts that they're not overly choosy and they'll use the perches they're used to. In other words, your mileage may vary.

 

[centrarchid]

I question the negative impacts of round perches on normally proportioned chickens. My chickens are very capable fliers and can live a decade or more yet have never seen problems with breast. Breed selection needs to be considered.

 

[pipdzipdnreadytogo]

Very true point. And I believe they never actually looked for keel deformities in that study, but instead tested how much pressure was applied to the keel by flat versus rounded perches, and then assumed the pinpoint pressure of rounded perches was the cause of deformities. There is mention of high incidence of keel deformities in layer houses equipped with perches, but no actual work cited on a causal relationship between these deformities and the perches--simply assumptions that this is the cause.


Edited to fix a grammatical error.

 

[Shadrach]

'Digital tendon locking' actually does occur in the Galliformes, including Gallus gallus. It's not a specific trait to Passeriformes and their closer relatives. In fact, the same tendon locking mechanism is present in a wide variety of species from many of the avian orders, including those that do not normally perch, such as Mallards. So the Galliformes may have split off much earlier than other bird species, but this mechanism apparently developed before then.

Also, it goes far beyond just the bending of the leg causing the toes to grip. There are actually rough patches along the tendons that 'mesh' with one another to lock in place. This is the same across avian orders with the trait, not specific to any in particular, and occurs early in fetal development. We know it occurs in Gallus gallus through dissection of the foot revealing the presence of these rough tendon patches.

As for perch width, this is a commonly cited study about chicken perches which concludes that flatter perches are better for keel health, but rounder perches are better for foot health. From that, I would assume that a flat perch with rounded edges would be the most optimal overall--but that's just my inference from the data given and by no means actual, proven science. The birds themselves seem not to have a preference, other than that they seem not to like round perches with smaller diameters (ex. in the above article, a citation states that the birds preferred ~4-inch diameter round perches rather than ~1-inch diameter perches). Please note that birds in these studies are usually ones that had no access to perches before and were given the option, not ones who had experience with X size perch and were given the option of Y size perch. So, I would gather from this and from previous posts that they're not overly choosy and they'll use the perches they're used to. In other words, your mileage may vary.

The study I read mentioned the locking mechanism. You've made the point indirectly that perch texture also plays a role and this was also mentioned in the study I read.
I've been looking for the paper but I just can't find it. It was someones phd thesis.

 

[Shadrach]

I've just finished getting everyone in for the night.
I have one hen that goes up a tree to roost except when she's planning to sit and when its raining. I've been getting her out of the tree in the evenings for over five years.
Tonight, I put two Bantams back into the tree after they had come down to eat, one male and one female; I now have two Bantams and a cross breed up a tree roosting on their usual branches.
I left them there until it was almost dark and armed with my T pole and a head-torch I got them all out of the tree by placing the T at the end of the pole between their ankle and knee joint as usual. None of them straightened their legs when they stepped onto the pole!
The movement is at the hip. The foot uncurls, but the leg doesn't straighten.
This doesn't match the information given by those who describe tendon locking as how the chicken grips the branch. According to the tendon locking theory the leg would have to straighten for the foot to unlock, wouldn't it?

 

[pipdzipdnreadytogo]

Not true. That assumes that this is some sort of robotic locking mechanism that overrides general muscular control. The tendon locking mechanism basically adds friction to the tendons in certain locations, meaning it takes more force for them to move across each other when in these positions. This aids in holding joints in place once the bird has crouched down, which is advantageous for such endeavors as perching on limbs, but the mechanism does not prevent movement altogether. The bird must simply apply more force in order to move those muscles than it would without those rough patches.

 

[Shadrach]

Not true. That assumes that this is some sort of robotic locking mechanism that overrides general muscular control. The tendon locking mechanism basically adds friction to the tendons in certain locations, meaning it takes more force for them to move across each other when in these positions. This aids in holding joints in place once the bird has crouched down, which is advantageous for such endeavors as perching on limbs, but the mechanism does not prevent movement altogether. The bird must simply apply more force in order to move those muscles than it would without those rough patches.

I've misunderstood the nature of the tendon locking mechanism then. I had taken it to be a robotic/mechanical mechanism that required a particular leg position to unlock.
How is the friction added? Does the chicken have control over the position, or texture of these rough patches?
I have looked at various explanations but I haven't found anything that explains at sufficient depth.