Yes, provided the cat has all four paws with claws and makes a good pounce. However, chickens (particularly roosters) have sharp spurs on the backs of their feet for fighting, and they can be vicious with their beaks, so it wouldn't be a sure-shot win for the cat.
In most instances when a cat is confronted with a grown chicken, both animals choose to walk away from the battle. An adult cat facing a chick is a different matter entirely, and the chick is generally cat food.
Yes, of course! Cats are strict carnivores and predators, and will eat everything of their prey. The organs of the prey are full of essential fatty acids (Taurine, for example) and other nutrients that a cat needs. Even bones provide the cat with calcium and are easily broken down and digested in the cat's stomach.
Even our beloved pet cats are perfectly capable of safely eating a bird as that is what they have evolved to eat, amongst other small animals and birds. Such small animals are easy to hunt and catch, and due to the size of the prey, the bones are easy to crunch up.
yes
To help them catch small animals such as mice and birds, which they eat.
because they are birds, and cats eat birds if they can catch them.
sometimes they will
Yes, some pet cats do eat birds and rabbits.
All domestic cats like fish.
no because cats like to eat birds
Cats do occasionally eat birds.
It would probably be the birds, if they are eating the grasses. Fleas eat the blood of the birds and cats, the cats eat the birds.
They eat worms rats 
cats like to chase and eat birds, and birds like to fly to get away from cats.
Cats and other birds
Domestic Cats obviously don't eat as much as other cats due to their size.