
Hi Hayley, I don't think it's a good idea at all to leave food down all day. I just encourages the dog to be more picky than he already is. You were doing the right thing already. Leave it down for 15-20 minutes, then take it away, no messing about, if he's hungry, good. He'll eat it next time he's offered if that's the case. Keep at it, don't let him get the upper hand, you are in charge, he eats when you say so.
Sorry if that sounds harsh, it's not really, but he must get the message, eat it or lose it.
Dawn R.