Genetics for Dummies

     Welcome to Genetics for Dummies! I thought this might be helpful to those wanting to know more about chicken genetics, particularily if you're interested in breeding. Not that I'm saying your dumb or anything - not everyone can be a genetics professional. This is just a post about genetics in general, and a little bit about basic chicken genetics. I had to do this first, before I could describe leg feathering and frizzles and rumplessness and extended black; well, we'll get there!

Genetic Terms

     Here is a dictionary of genetic terms I'll use, throughout this article and later articles. If you come across a word you don't know, come here and you might find it and its definition. Have at it!

Allele:
One of 2 or more forms of a gene that are found at the same place on a chromosome

Chromosome:
A threadlike structure that carries genetic information in the form of genes

DNA:
Deoxyribonucleic Acid, which is the carrier of genetic information

Dominant Gene:
An allele that is dominant, as in it can overpower a recessive gene when the pair is heterozygous.

Genotype:
The genetic makeup (as in a chicken that is o+/o+, which is the genotype of a White Egg Layer - see phenotype)

Heterozygote:
A chicken that is heterozygous for a gene

Heterozygous:
Genes come in pairs, the alleles can either be alike or different. If it is heterozygous, it is different (for instance, O/o+ is heterozygous)

Homozygote:
A chicken that is homozygous for a gene

Homozygous:
Genes come in pairs, the alleles can either be alike or different. If it is homozygous, both alleles are the same (for instance, O/O is homozygous)

Mutation:
When a gene can be changed, like, the mutations of extended black. Like most genes it can either be e+ (duckwing/light brown) or E (extended black), just the same as most other genes. But that gene has mutations - E^R (birchen), E^Wh (Wheaten), and e^b (partridge/brown). The mutations can be in the same gene pair as e+ and E.

Phenotype:
The visual description, what you see when you look at the chicken (as in White Egg Layer, which is the phenotype of a chicken that is o+/o+ - see genotype)

Punnett Square:
A diagram used to show the outcome of a cross between 2 chickens

Recessive Gene:
Recessive genes will only show in a homozygote, if it is heterozygous the dominant gene will overpower the recessive gene and the recessive gene will be hidden by the dominant gene.

Sex-Linked Genes

     Ever heard of sex-links? They're hybrids, and you can tell the males and females apart by their color at any age. How does that work? Sex-linked genes. Here's how.

     In humans there are genes that determine whether you are male or female, most people know about these but they are XX in females and XY in males. This means that your dad determined your gender. In chickens, instead of using X and Y, they have Z and W. It's backwards of humans - the hen determines the offspring's gender, because they are ZW while the roosters are ZZ.

     On the right is a diagram. It shows the barring gene (which is sex-linked and how Black Sex-Links work), Silver (which refers to the ground, base color of the bird. A chicken can be silver based or gold based wildtype or "golden", its sex-linked), and Mahogany (which is not sex-linked, for reference).  

     The green shows the genotype of the two chickens, while the purple labels the gene on the far left and shows the phenotypes. As you can see, the sex-linked genes are those that only have one allele on the hens, while having 2 alleles, as usual, on the roosters.

How to Use Punnett Squares

     I would like to introduce you all to George, my imaginary friend the Ameraucana rooster. Secondly, I would like to introduce you to Hannah, my imaginary friend the Barred Rock hen. We are going to breed them, but we want to know what color their eggs will be. Even though George doesn't lay eggs himself, he has genes for eggs. His genes are O/O, which means that he is a blue egg layer. Hannah, on the other hand, has genes that are o+/o+, which means that she is a white egg layer. You see, Barred Rocks lay brown eggs, but brown eggs are actually white eggs, they are just covered in a brown paint called a 'bloom'. Green eggs are actually blue eggs with a bloom over them.

     So we have George (O/O) and Hannah (o+/o+), and now we want to breed them. To find out what
color eggs their offspring will lay, we have to use a punnett square. George's genotype is on the top, each allele is over its own box. Hannah's genotype is on the left side, and each allele is beside its own box. Then, you look at the alleles touching each box and put them inside the box, making a new gene pair. Since all the new gene pairs are the same, we know that 100% of the offspring will be O/o+. Since blue eggs (O) is dominant, all of them will lay blue eggs.

     But what happens if we have two chickens that are O/o+? Lets call them Jim and Lori, and they both have a heterozygous O/o+ genotype. What happens if we breed them? Look at the punnett square to the right to find out. It works the same way this time as it did last time. Breeding Jim and Lori results in 25% of the offspring being homozygous white egg layers, 50% being heterozygous blue egg layers, and 25% being homozygous blue egg layers.

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Questions? Comment or send me an email at reavisridgepoultry@gmail.com

 

Please comment below! Follow me on Google+ in the upper right and g+1 me at the top left on the bar! May you have a wonderful day full of chickens.

Introducing New Chickens (with pecking order help)

Broody Hens & Chicks

     You go to your coop, locking everything up for the night. All is well - until you realize you're missing a chicken. Frantically, you look around, searching for her. Then there she is, in the nest box.

A broody feeding her chicks

Laying an egg this time of night, when she should be roosting? No! Your girl is broody, now what is it you're supposed to do about it? (Find more information about broody hens here)

     Other hens may get in the nest box with your broody, crushing or cracking eggs. To avoid this you might want to move your girl to another location, but only at dark as you don't want to upset her and make her come off the nest.

     When the little fluffies have hatched don't worry about them getting hurt by bigger chickens. Let them out to play and have fun! Mama will take care of them, she will fight other chickens to keep them safe. NOTE: If a hen has several chicks, she might stay with the majority. So if one gets caught in the fencing and two more get trapped on the other side of a fence, she might not be able to help them. Until they are bigger you might want to help her keep an eye on them yourself.

Mixing Chicks

     Mixing a wide variety of ages together might be stressing for them, especially in smaller groups. Most people go by two weeks, if they are more than two weeks apart in age do not mix them until they are older. If you have one week olds, you can put them with two week olds, three week olds, or younger chickens, but not four weeks, five weeks, and so one. That's just the general rule of thumb.

Mixing Different Breeds

     I have come across many people who say, "Well, we had them separated because they were different breeds and somebody told us we couldn't mix different breeds in the same pen," or something similar. Of course many people do have flocks of Orpingtons or flocks of Delawares, and a flock is made up of a single breed, which is perfectly okay. If you plan on breeding Orpingtons or Delawares you should probably have a flock of Orpingtons or a flock of Delawares. Yet you can put your Orpingtons in with your Delawares, that would be called a mixed flock.

     I have a mixed flock, they are my layers that lay me lovely eggs that I eat and sell (for eating). Some breeds will do fine in a mixed flock, others not as much. For instance, Silkies sleep on the floor because they can't fly with their silkied feathers. I do not own Silkies myself, but Silkie owners say they sleep on the floor under the roost and will get pooped on. For this reason, I do not want to get Silkies because I have no where to put them except for my laying flock, and I don't want them in a mixed flock, I want a flock of Silkies (maybe some Sizzles too...). Salmon Favorolles owners have said they think they would do better in a flock of Favorolles than a mixed flock because they are very timid and always at the bottom of the pecking order.

Rooster Behavior & What to Do About It

     There are many opinions on rooster aggression. I'm just going to try to give you the facts and my experience with this, so please if you have an aggressive rooster do what you feel is the right thing to do. I'll start by telling you my story.

     In the spring, around Easter, I had gotten four little chicks. A Light Brahma, a Golden Laced Wyandotte, and two Black Jersey Giants. Being my lucky self I ended up with 75% cockerels, the pullet one of the Jersey Giants. What I didn't know was that the Jersey Giants were from a local breeder of pet quality Giants, and he had a very aggressive line.
 
     Generally roosters get sort of cocky when they are about a year old, they have lots of hormones going on and stuff, and then they'll quiet back down and be a good rooster. My black Jersey Giant cockerel, named Ashe, attacked my grandmother one day before he was even six months old, or about it. Then the next week I bent over in the run to pick up a feather and he hit the backs of my legs. We just kept hoping he would stop, get better maybe. We fought him back (this didn't work, he would just try again a couple weeks later), among many other things. We caught him and trimmed down his toenails and spurs so that he couldn't hurt anyone. We did what people online said to do, holding him and pushing his head down repeatedly until it stayed down. Nothing worked.

     What were we supposed to do? Sell him? That would just dump our problem off on someone else. No way would we breed him, we didn't want any little Ashes running around attacking people (many people say aggression can be passed on, which I agree with. This entire line was aggressive). Now my pullet, his sister, is a wonderful girl, currently top of the pecking order, occasional broody hen, and loves treats. He was another story entirely. I stopped wanting to go see my chickens because I didn't want to be attacked again.

     We were constantly shifting around the three roosters, our ratio was way off, which I'm sure didn't help maters. Anyway, the Brahma and the Wyandotte were itching to fight each other, we had the Brahma separated (more about that later) and the Wyandotte had always been #3. He couldn't beat Ashe so he was going to try to beat the Brahma. The final straw was when we separated all the roosters from the hens. The Wyandotte got his chance at the Brahma, and was simultaneously fighting with Ashe and Ashe was trying to break it up and the Brahma just wanted to fight the Wyandotte - it was mad in there. No one got hurt, the Brahma was so tired that when we set him up on the roost he fell off and we had to put him back up again. Ashe ran into a corner of the coop and got stuck and I thought he had died, squished up in there, but he was okay. Then they went to bed.

     Really, I couldn't bring myself to eat Ashe, no matter how awful he was. So we packed up Ashe and the Brahma and went to go trade them for a couple hens (the guy we traded with was a friend of ours and was planning on eating them, so all was well). The Wyandotte became aggressive because Ashe wasn't there to keep him in check, and we ended up eating him too.

     Please - learn from my mistakes. Don't keep a mean rooster who could injure you or someone else. Really, a lot of my problems would have been solved if I had just eaten him (or had someone else slaughter him) in the first place.

     Now, about the Brahma. He was separated from everyone else because, well, lets just say he was very hormonal. It came to the point that I thought he would kill some of my little Leghorns, even with Ashe spending all his time trying to stop him. It was really worse because Ashe really couldn't do anything about it so he just did the same as the Brahma, trying to prove he was just as good, I guess. Other than that, he was a great chicken in general. He was never mean to me, he always seemed to like me as much as the hens did. But he still had to go.

     If hens are over mated, they will start loosing feathers. You can buy them saddles to let them regrow. Sometimes a rooster's spurs will slice the skin under a hen's wings, this happened to one of my Barred Rocks. Just make sure the wound stays clean and it should be okay, so long as she is separated from any roosters while it heals. You can file down spurs to help prevent this. It you don't have enough hens per rooster, it can also cause these problems. Keep in mind the Brahma was quite a severe case, most roosters have favorite hens that will have feather loss and you really don't need to get ride of your rooster, but a saddle would help her feathers grow back.

     Roosters can be great pets, just like a hen. However not all roosters will turn out as suitable pets, you just have to raise them and keep the good ones.

A word on aggression and fertility ~
     Studies in cattle have shown a positive correlation between low fertility and high aggression. It's possible the same thing happens in poultry. One theory is that the extra aggression in males is caused by the testosterone not being utilized correctly, which would potentially explain the increase in aggression as time goes by. The testosterone would just remain in the bloodstream in aggravating and useless amounts. So even if your aggressive rooster is the closest you have to the Standard, he might have low fertility.

When to Introduce Chicks to Older Hens

     Chicks should be 3/4 the size of the older birds when introduced, and they should have their 'grown up voices', meaning they aren't peeping anymore. Separate them so that they can see each other but they can't fight, so that they can get used to each other and get some of their pecking order sorted out. This not only applies to chicks, but any new chickens you are introducing to your current flock. It will take them a while to sort out their pecking order, so just give them time. They will sort it all out on their own.

     There's more to consider. If the chickens you want to introduce are too young to eat the big chickens' feed, you will have to wait until they are older to introduce them. Keep this in mind when introducing young birds to older ones.

Space & Ratios

     How much space does a chicken need? If chickens are too crowded it can cause feather picking and toe picking among other such problems. To avoid this, you need to make sure your chickens have enough room. The general rule is to have 4 sq. ft. of coop space and 10 sq. ft. of run space per chicken.

     How many hens does a rooster need? Roosters need to have several hens available to avoid over mating, which can cause feather loss and other problems. For heavier breeds, 8 hens per rooster should be sufficient. For lighter breeds, 12 hens per rooster and in bantams 25 hens per rooster. Of course this will vary depending on how active your rooster is. If you have too many hens the rooster many not be able to get around to all of them, and you will have poor hatchability. Too many roosters and they may spend more time fighting than mating, also resulting in poor hatchability. Sometimes there will be ratios of about 4 hens per rooster in breeding pens, but only for shorter periods of time so as not to stress the hens.

More Helpful Tips

     Particularly bossy hen? If you take her away from the flock for a time, somewhere where they will not see her, they will forget about her. Then you can reintroduce her and she will no longer be so high in the pecking order. Then, they will boss her around until she gets back to her old position, if she does.
    

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     Please learn from the mistakes I have made and comment below! Follow me on Google+ in the upper right and g+1 me at the top left on the bar! May you have a wonderful day full of chickens.