http://www.citygirlchickens.com/things_chickens_should_not_eat.html Found this on what not to feed chickens, mine like tomato though and had no ill effects
Mine love tomatoes also, the article says tomatoe leaves though and I've never seen them eat the leaves in the garden, just the tomatoes.
The tomato fruit is perfectly fine to feed chickens, and most of them love it. However, tomato (along with potato) are members of the nightshade family and the green parts (leaves, stems) of them are toxic. They should never be fed to chickens.Mine love tomatoes, too. They also occasionally eat the leaves and there has never been a problem. Mine will eat almost anything green including ivy and ice plant. I used to have a problem with an overgrowth of both but my chicken weeders have taken care of that for me.