A little history I currently have a 5 year old pit and two one year old boxers. My male boxer has started throwing up at bed time in his crate. We are unable to locate any items that he has eaten. We have noticed that he does not chew up his food but swallows it whole. We have also noticed some grass in his vomit but not all the time. I recently put apple cider vinegar in their water bowl and we thought that was the problem so we went back to plain water. However he is still throwing up at bedtime. Our dogs are out all day with my husband and eat and drink with no problems. The only time he is sick is at night. Does anyone have any suggestions. We lost our first baby to stomach cancer one year ago. So we want to catch this if we can. Also his father is a DNA registered stud would that help to rule out certain diseases. What is strange is our two boxers go everywhere together and our female is not sick that is why I am so worried, she is the one that will eat anything that won't eat her first. Any suggestions.