What is the simple subject in the following questions?

1. Come to the state fair.

2. Notice the color of its feathers.

3. Alan's prize rooster is there.

I think the answers are the following.

1. fair

2. its

3. rooster

Am I correct?

Yes, you are correct! In each of the given sentences, the simple subject is the main noun or noun phrase that the sentence is about.

1. Come to the state fair.
Simple subject: fair

2. Notice the color of its feathers.
Simple subject: feathers

3. Alan's prize rooster is there.
Simple subject: rooster

To identify the simple subject in a sentence, you can ask yourself "Who or what is the sentence about?" The answer to that question is typically the simple subject. In sentences like the ones given, it is common for the simple subject to be a noun or noun phrase.

Number 3 is the only one that is correct.

Numbers 1 and 2 may be confusing to you because the subject isn't actually stated. The subject in both sentences is the understood "you."

(You) come to the state fair.

(You) notice the color of its feathers.