Who was eligible to participate in the lottery in "The Lottery"?

Everyone in the town participates in the lottery, and those that are old or infirm have someone draw for them. 

The lottery is a village tradition.  It is such an important tradition that even though it is completely barbaric the townspeople see nothing wrong with it.  Whatever the original reason for the lottery was, it is clear that they keep participating because they always have done it this way, and this village changes nothing. 

Perhaps the most difficult to stomach is that even small children participate.  Take the case of little Davy, who is so young that he has to have help drawing his paper slip. 

Mr. Graves took the hand of the little boy, who came willingly with him up to the box. "Take a paper out of the box, Davy." Mr. Summers said. Davy put his hand into the box and laughed. "Take just one paper." Mr. Summers said. "Harry, you hold it for him." Mr. Graves took the child's hand and removed the folded paper from the tight fist and held it while little Dave stood next to him and looked up at him wonderingly. 

One man, Old Man Warner, comments that this is his seventy-seventh time participating.  Apparently, neither the very old nor the very young are immune.  The only way you get out of being actually present at the lottery is if you can’t physically go, such as Clyde Dunbar’s broken leg.  In that case, his wife drew for him. 

Everyone also participates in the stoning itself.  Before the lottery the little boys gather rocks.  When Tessie Hutchinson is chosen, someone even gives little tiny Davy Hutchinson a few pebbles so that he can help stone his own mother to death.

Jackson makes it very clear that no on escapes the lottery.  Children, the elderly, and even people who are sick or injured all participate.  Individuals draw for families, making the process seem even more demented.