Have you got a current driving licence? http://damplips.in.net/ damlips.com  Dogs are scavengers, and this tendency to gobble anything remotely edible will be exacerbated because this dog has had to fend for himself in his past life as a stray. You should try to stop him from doing this, first because he is upsetting his digestive system by eating stuff that irritates his stomach, and second because he is probably eating slugs and snails that he encounters in the garden, and these carry lungworm which can cause serious illness in dogs. To change his behaviour, give him a food-stuffed interactive toy as soon as you let him out in the morning (Kong or Squirrel Dude dog toys, both available online). When he learns that he can extract tasty, nutritious food by playing with the toy, he’ll be less likely to want to browse for morsels around the garden. To minimise the risk of lungworm, apply a once-monthly anti-lungworm spot-on, available from your vet.