Hi,
I just now saw your message and I hope your puppy is eating well now. I went online to see if there would be information about this problem for your Labrador and I did see articles there. You can go on to a site called
www.labradorsite.com and they have some very useful information there to help you out. It also says that illness could be a reason your baby is not eating and if so you should seek vet help. It could be he is being fussy too. But if you either go online to find an answer or ask your vet I think they would be two good choices. I hope you find the answer and your precious one starts eating soon and all is well. Let us know how it goes and sends us pictures if you would. We like pictures.