Hello & Welcome to YT!!! Yes, 5 months is a normal age for pups to start loosing their teeth. No you do not need to stop feeding him the hard kibble. In fact, the kibble is good because it will help the other teeth to loosen and fall out as well. Provide him with plenty of chew toys which will help also, otherwise he may begin to chew on things that you wish he wouldn't. Good luck!
