Thank you for your question!
Unfortunately this is a habit of many dogs. Dogs are natural scavengers and do not see eating faeces as repulsive as humans do when they decide to consume it. The possible reasons vary from behavioural to medical.
Medical conditions that cause a decreased absorption of nutrients from the gut can lead to coprophagia (eating their own poo). Hence a checkup by your veterinarian is the first step- they will perform a physical exam, discuss diet and examine a sample of your dog’s faeces for evidence of parasites. Sometimes the faeces will be sent away for testing if a digestive enzyme deficiency is suspected.
It is worth noting that an increased appetite- which can can occur with certain medical conditions or drugs (steroids for example) or with a low nutrient diet-can lead to coprophagia also.
Attention seeking - it may seem naughty to us humans but sometimes dogs will eat their faeces to get our attention- and it generally works!
Boredom- Dogs who are in isolation or bored because they are left on their own for long periods will sometimes start developing this habit
Punishment - dogs who are punished for defecating in the house can 'eat the evidence' so to speak to avoid getting in trouble.
So how do you overcome this problem?
Make sure to clean up after both dogs as soon as they relieve themselves.
Try and keep your dog mentally and physically engaged, daily walks and playtime are essential for keeping him healthy and stimulated. Make sure he has plenty of toys to keep him occupied when he's alone.
Pay particular attention to his diet to ensure it contains essential proteins, vitamins and digestive enzymes. Vitamin B deficiency has been reported to be a culprit for dogs eating their own faeces so choose a premium quality dog food which is balanced- your vet can advise you.
Avoid punishment if your dog eliminates in the house, as studies show it is ineffective and can bring on additional stress or anxiety which only reinforces the behaviour.
My best advice as a first step is to consult with your vet to rule out any underlying medical problems. If your pup is given a clean bill of health, keep his environment clean of faeces as much as possible, provide him with a balanced diet and exercise to stimulate his mind. Walk your dog on a lead, if he does approach any faeces, tell him to leave it and distract him with praise or a treat. If your dog is interacting with you, he'll have less chance to pick up poo. I hope this helps- Good luck!
- Dr Alex Hynes