The noun 'chicken' is a singular noun as a word for a type of bird. The plural noun is 'chickens'.
The noun 'chicken' is an uncountable noun as a word for the meat of this type of bird, a word for a substance.
The noun 'chicken' is a common gender noun, a word for a male or a female bird.
A noun functions as the subject of a sentence or a clause, and as the (direct or indirect) object of a verb or the object of a preposition.
Example uses:
Note: The noun 'chicken' is also an informal word for a contest between people in which the first person to lose nerve and withdraw from a daring or dangerous situation or activity is the loser.
The word 'chicken' is an informal adjective used to describe a person as timid or cowardly.
The chicken just crossed the road.
The noun chicken (the creature) is a countable noun; one chicken or a dozen chickens. The noun chicken (the food, a substance) is a mass (non-count) noun; units are expressed in pieces of chicken, parts of chicken, pounds of chicken, etc.
It can be, in context. If referring to an individual bird, then it is a regular common noun. If it is talking about chicken meat, then this is an uncountable noun, there is no 'a chicken' when talking about chicken meat.
It is a noun (chicken pox is the name of a specific disease).
The noun 'chicken pie' is a singular, common, compound, concrete noun; a word for a thing.
There is no specific collective noun for chicken grains, in which case a noun suitable for the situation is used; for example a sack of chicken grain; a bin of chicken grain; etc.
roast chicken
You can use marches as a noun or as verb. An example of marches as a verb would be "He marches like a chicken" An example of marches as a noun would be "All marches begin with a single step"
No
Kentucky Fried Chicken is a proper noun, it is the name of a specific company. Proper nouns are always capitalized.
Chicken
chicken nuggets