With reference to health concerns, when purchasing a Belgian Shepherd; dogs should have been certified clear of hip dysplasia and eye diseases. In Canada Breeders may have either a letter from the University who read the dogs x-rays or if registered in the U.S. data base should supply you with a registration number. All eye clearances should be registered with C.E.R.F. Most recently, breeders are testing for thyroid. A breeder should give you a written health guarantee.
The other health concern is seizuring. It has proven very difficult to eliminate, because it's mode of inheritance is not understood and an animal may not start seizuring until after it is three or four. By which time it may have been bred. Also the dog may seizure only a couple of times a year and the owner may never know. The overall prevalence of seizuring within the breed has recently be estimated at about 12%.
Anaesthetic - Belgians have a higher than average death rate when put under Anaesthetic. This is due to the muscle to fat ratio. Each time one of my dogs undergoes any type of surgery I always remind my Vet of this fact, and she always reminds me that she treats my Belgians as she does site hounds.
A good majority of Belgian Shepherd Dogs are high strung, because of this poor temperament does crop up. Avoid puppies that are shy, timid, fearful or overly aggressive. You should also avoid litters where the mother is like that.
A Belgian should be willing to meet you, and should not avoid you. They may be cool towards you and not welcome overzealous petting, this is not unexpected. Belgian Shepherds love their people and are extremely demanding of their attention; but unless he has met you a few times, he does not consider you his long lost buddy.
Visit as many breeders as possible whether or not they have puppies and whether or not it is the variety you want. This will give you a good idea of what a Belgian is like to live with.
When you purchase a Belgian puppy, most Belgian breeders recommend you enrol in a good obedience class.