dip the rats head in chicken broth. most likely he will eat it, i have had my carpet do that to me when i didnt get the exact same size rat and she wouldnt eat it but as soon as i dipped it in chicken broth she beat the brakes off it persay lol. i had a boa years ago also and i did the same to him when he wouldnt eat. cant hurt to try and the broth isnt but liek 89 cent to a dollar so it isnt to expensive not to try.