Listen to Nik...bowls that trick or inhibit the dogs from
wolfing their food down OR breaking their meals up into many smaller meals are the best suggestions.
We have a recent thread regarding bloat, which is a death sentence for most dogs. Heed the warning here, feed at a slower rate, especially if it is kibble only. Have time to assess that they are processing the food correctly. Most bloat cases can be referenced back to deep chested dogs (mastiffs and others above 95 lbs), additionally, there are issues with kibble only meals, exercise after meals, etc.,
Take a chance to review this and the accompanying videos from YouTube. The Best Defense Is A GOOD OFFENCE. Be Your Dog's Hero...slow the chow situation down, even if you have to hand feed the entire meal...which has great bonding issues...but allows them to digest the food without building up dangerous gas which can twist and turn a bowl and cause horrific pain and sudden death.
http://www.mastiff-forum.com/index.php?threads/bloat-question.30355/#post-376222