Like Hedonic_Treader points out, I think you have the longevity wrong, which may make the question somewhat difficult to answer. If 8 chicken lifespans represents one year, then saying "I think factory farming one chicken balances out one human life" represents an answer of 8, not an answer of 1.

I don't think that has a huge impact on the analysis, though, because the breakdown at present looks like this (and I would expect that, at most, this would impact the Less than 1 group):

Less than 1: There are 2 0.4s and a 0.5. Low: Two 2s and a 20. Medium: 2 100s and a 1600. High: 2 millions, one 10 trillion, and one quadrillion.

About half think that chicken lives and human lives are roughly comparable; about a quarter think human lives are more valuable; about a quarter think human lives are much more valuable (of the 13 who have responded to this poll, which is much less than the number which responded to the other poll).