Hearing and Sight
Chickens have an acute sense of hearing; they don’t have an ear lobe but have a well developed ear. They have panoramic vision of about 300°, and binocular of about 26°. They can’t rotate their eyes very much, therefore, move their head to follow objects. Their ability to discriminate color is yet to be learned.
Communication
A large part of their communication is postural, which signifies both threat and submission. But I have observed vocal communication skills which indicated a wide variety of sounds about:
Mating
Contentment
Food
Danger / Fear
Submission
Territories
Distress
Warning
Nesting
Laying eggs
Taste
My observations on the chicken’s ability to taste are limited to their dislike of food that is bitter, sour, too sweet, or too salty. They have about 340 taste buds in comparison to a human’s 10,000. They don’t like drinking water that is warmer than their body temperature, but show a liking for near-freezing water.
Smell
There is very little research available about a chicken’s sense of smell, or if it’s of any significance to them at all.
Observe your Chickens
The best way to better understand your chickens is to watch them and observe their behavior and their character traits. Every member of your flock has likes and dislikes, and a personality all their own. In time, you will be able to identify behaviors by a specific sound or call. There is a structured language among your flock members, listen, watch, and learn.
This is a controversial question indeed. Many chicken keepers are worried about their birds consuming any kind of chemical, certainly a valid concern. But, I think everyone should be equally concerned about the health of their birds.
Like anything else, education is the key to better understanding. After researching whether or not I should worm my own flock I stumbled across this article on Worming Chickens, it discusses a product called Flubenvet. I know about this wormer, but considering Flubenvet isn’t available in the United States it’s not much good to me.
Nevertheless, I researched it again and it led me HERE with more information on how to use Flubenvet and where to purchase it online. The Backyard Chicken forum was also helpful with another online source.
TBN Ranch Chicken Keeping Resources 