D. The text below has been jumbled. Arrange the paragraphs in the correct order to make a full story.

Date: 2015-10-07; view: 551.

C. Read the text again and answer the following questions in your own words.

1. What was the disease against which the first attenuated vaccine was discovered?
2. Why does a careful study of avian immune system help us to understand better the rules of evolution?
3. What practical application will we get from these studies?

4. What are the differences between mammalian and avian immune systems?

1. What is in author's opinion the only way for a full understanding of the immune system?
2. How can the studying of the avian immune system be useful for science and for people?

7. What qualities help poultry to be a major source of protein for humans?

8. Why cannot chickens be called "mice with feathers"?

9. What particular qualities of the chicken MHC can you name?

10. Why does the discovery of “dinobirds " provide a major incentive to careful study of avian immune system?

Rats and Mice are the Most Common Chicken Predators.

(1) Eggs may also be removed from the nesting box and taken to the rats' lair along with feathers and bedding that the rats use for nesting material. The feathers are collected from the floor or plucked from the chickens.

(2) Some birds survive but lose toes, feet and even legs to the rats' incredibly sharp teeth. Any chickens showing signs of having been attacked by rats must be checked out by a vet immediately because of the risk of disease and infection resulting from the near-death encounter.

Eggs are easy targets often consumed on the spot, leaving telltale pieces of broken eggs behind that can lead a poultry-keeper to erroneously believe a member of the flock is responsible.

(3)Chickens are most in danger from the presence of rodents at night, when the birds are roosting in their coop. Rats commonly emerge in the darkness to kill chicks and even bantams (miniature chicken breeds), dragging prey back to their lair.

(4) Another form of poison is much slower-acting but will kill the rodents over time, causing death by dehydration that results in no attendant smell of decomposition. This type can sometimes be safe to use in the vicinity of humans and other animals.

(5) Poison generally comes in the form of lethally dosed corn or wheat. This is as dangerous for chickens to eat as it is for rats and mice, so it must be located underneath coops in places where the birds cannot reach no matter how hard they try. Unless dead bodies are found and removed, they will decompose in situ and smell.

(6) Both mice and rats will steal from poultry feeders, use drinkers and harvest corn and layers pellets from the floor of the run and coop.
(7) Mice being smaller aren't as big a problem as rats. They don't steal chicks or bantams away, although they will steal feathers—often nibbling at tail feathers in particular - and their droppings can be consumed by the chickens, spreading disease in this way and by urinating on food and in drinking water.

(8) Rodents are kept under control by using either poison or traps, or both. Traps are generally safer for chickens but it is unacceptable to release the captured rats elsewhere. They must be killed, which is a job not everybody feels able to do and must be done quickly and humanely, the same as with any other animal.