Why wont my lab. eat?

Question
my lab has a hurt paw, i believe she could have stepped on a thorn or something she walks on her 3 legs except her back left leg where shes hurt, she wont drink or eat her food, is this normal because shes hurt?

Answer
Normally, nothing will stop a lab from eating.  

I would take the dog in to see the vet as soon as possible.  If you have looked the foot over thoroughly and there is nothing IN the pad, in the webbing between the toes, the toes aren't broken, the nails are intact, the problem could ACTUALLY be the knee.  Many times a torn cruciate ligament looks like a foot problem because the dog won't bear weight on that leg.