It's the whole hilarious "Hey, I'm a chicken! Eat more beef! So then you're not eating me!" thing. Which when you think about it really makes more sense than the usual Suicide Food phenomenon we're all so used to, of animals telling us to eat them.
It was a play on the awful Chik-fil-a chain. They have cows all over holding signs that say "Eat mor chikin" get it? Just be glad you don't have them in Seattle, because the food is terrible.
And by what reasoning does Mr. Hatter assume the perps dislike chicken? MAYBE, the thought of killing and eating a succulent, giant mutant chicken was what compelled them to shoot in the first place.
Best Suicide Food for me was the talking cow walking among the tables in Restaurant at the End of the Universe by Douglas Adams, saying something like "my ribs are particularly succulent today"...
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