"Feed the Dog" is (naturally) Good Dog (Plain) free font by Ethan Paul Dunham (Fonthead Design, 1996)

Strangely enough, the same font is also used for the other 2 images, although I can't fully understand what is the relation of Good Dogs to Balloons and Apple Catchers...

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I found it using Find my Font - http://www.findmyfont.com

Thank you very much fvilanakis :) I guess the relation to ballons and apple catchers will remain an unsolved mystery ^^

Oh thanks Steve... now I see!
that explains everything: They were actually poem verses :)

I really wasn't sure what Walker meant or if he was serious.