1. Does the rescue spay/neuter before adoption? Both rescues i work with absolutely require that an adoptable dog be S/N before placement- no vouchers for later. Puppies are fostered until they can be S/N.
2. Does the rescue charge an adoption fee? Almost all do...and should, to keep costs under control. $200-$300 is common, and fair, considering the dog is S/N and should be up-to-date on vaccinations, heartworm and flea treatment. One of mine charges $350 for dogs under 6 months, $250 for dogs 6 months - 3 years and $150 for dogs 3 years+. Outrageous fees are IMO ridiculous ( I've seen rescues charging an $800 adoption "fee" though and there are some mills masquerading as rescues
3. Is the rescue breed-specific or all-breed? Breed specific rescues should be recognized by the parent breed club. Be very careful with all-breed/mix rescues, especially if they are charging high adoption fees and labeling dogs with cutesy names like labradooble for a lab/poodle cross. ... they are generally false rescues. Does the rescue encourage adoptions where the dog is going to be used for the purpose for which it was originally breed? For example, a sporting dog rescue should not mind if the adoptee is going to be used for hunting IF the dog is capable of hunting (not gun-shy etc) ... and the rescue should have procedures in place to measure a dog's ability. I'm not saying that a rescue should be turning out fulled-trained bird dogs, but it should not act horrified if an adopter wants to hunt ..... or be willing to place an unsuitable dog with a hunter .... if that makes sense.
4. Do vets and trainers in the area know of the rescue? They should, because the rescue should be using their services...or those of a respected colleague. Who are the other foster families? Especially with breed-specific rescue, some of the foster families should be well-known breeders or trainers.
5. Did the rescue investigate you as much as you should be investigating them? Do they require that you take foster dogs to obedience classes or at least investigate your training abilities? Do they have guidelines in place for emergencies?
6. Where do they obtain the dogs in rescue? Breed-specific rescues may pull dogs from shelters in neighboring counties or states, but IMO should not be paying to transport dogs across the country. i would be extremely leery of a mixed breed rescue who transported dogs from other states.
7. What is their policy on euthanasia? What is their policy on aggression? What's their turn-over? How long does the average dog stay in foster care? How do they handle returns? Touting no-kill status is fine and dandy, but there are exceptions and those exceptions should be dealt with appropriately.
I work with 2 breed-specific rescues - we'll call them Rescue W and Rescue S. Both have a policy of not adopting any dog directly after it is surrendered or pulled from a shelter. Instead, the dog is fostered and evaluated for at least 5 weeks. This policy alone has greatly reduced the number of returns. For Rescue W, 1 dog of 34 adoptions in 2009 was returned. For Rescue S, 5 dogs from 64 adoptions were returned ....only one for aggression (establishing an actual bite history) and it turns out that particular dog had epilepsy ( manifested at 2 years old...and the dog was adopted at 10 months of age) He was returned to his original foster family and did very well with medication for 2 years before suffering another rage episode. This dog was humanely euthanized 2 days after the second attack.
Rescue W is more "lenient" with regards to aggression, especially aggression towards strangers, because the breed is known to be at best aloof with strangers. Because of the breed's tendency towards guarding behavior with a very strong work ethic, they place dogs very, very cautiously and evaluate potential homes very, very carefully before adoption. 95% of potential adopters are denied because they have no prior experience with the breed ... this is probably one of those rescues that people gripe about on Internet forums ;P
If a dog is returned for "aggression", you want to know as much as possible about the incident. Aggression that occurs in the first month or aggression towards non-family members, especially when it is only an aggressive display, is usually discounted, meaning that the rescue will offer the services of a professional Territorial aggression can be managed successfully and this type of dog can often go to another home with a more experienced owner.
Rescue S works with a sporting-class breed, so aggression is seen as a much more serious fault. ANY dog who is returned is placed with an experienced foster family and efforts are made to duplicate the situation where the problem behavior occurred ( except the dog being "hyper" ...it chaps my cheeks to deal with people who return a dog because he's too "hyper" when anyone should know the breed is high-energy). Rehab is generally successful with regards to things like food aggression/resource guarding, especially when a new owner is committed to following a protocol. Because this breed is generally known for its sunny disposition, territorial aggression is quite uncommon and a dog displaying territorial aggression even without a bite history is generally euthanized during the first fostering period.
It is very uncommon that fear aggression not manifest during the initial fostering period. In both rescues, dogs displaying fear aggression are generally euthanized after being evaluated. The amount of time and skill needed to successfully rehab this type of dog is simply too great. Yes, it is very sad, but the liability should an aggressive dog be adopted out again and injure someone is too great and the pool of suitable homes with accomplished owners is too small to do anything else.
All total I've rescued 9 greys, 3 of which we adopted. 
We are getting our first foster doggie tonight and we cannot wait!
