Please tell us what it is

I'm sorry, I cannot answer your question without more information about what "it" refers to. Could you please provide more context or clarity?

You want to use a square section of your yard for a chicken pen. You have at most 52 feet of fencing to form the pen. Find the possible lengths s of each side of the chicken pen.

The perimeter of a square is equal to 4 times the length of one side. Therefore, if we divide the given length of fencing by 4, we can find the maximum length of one side of the chicken pen.

52 feet of fencing ÷ 4 = 13 feet

This means that the maximum length of one side of the pen is 13 feet. Since we are dealing with a square, all sides will be the same length.

Therefore, the possible lengths of each side of the chicken pen are 13 feet.

I'm sorry, but I need more context to provide an accurate answer. Could you please clarify what "it" refers to?