There are SO MANY FACTORS that are going to effect this, and the very first thing that I always ask when asked about why eggs are not successfully hatching is "Did you take your birds to a Certified Avian Vet or Avian Specialist for a complete Wellness-Exam that specifically includes full Blood-Work, including a Metabolic Panel, and also an X-Ray of the female? There are a million different reasons why fertile eggs don't hatch, and the #1 reason has nothing to do with the external environment of the egg (especially if the female laid on it herself), but rather a problem with the developing Embryo, usually due to the physical health of the hen. So if you've never had your breeding-pair to a Certified Avian Vet for full Blood-Work, x-rays, etc., then that is absolutely where you need to start, because it's very likely an issue with your female's health and/or diet.
If the eggs are fertilized then it typically isn't a health issue with the male, though it can be, but rarely...9 times out of 10 when there is a problem with embryos developing correctly it has to do with the health and nutrition of the female.
****That being said, since the egg that you allowed the female to lay on/incubate also didn't hatch, that's a really strong indication that the problem really does have something to do with the health of the hen...While there are plenty of things that can go wrong with using an incubator, there is little that goes wrong with a female incubating her eggs herself, if she is in-fact laying on them. The other indication that something might be going on with the health of your birds, specifically the female, is that you only got 1 egg in two clutches, and the average eggs in a Blue and Gold Macaw clutch is typically between 2-3 eggs, with 4 usually being the max...So the fact that you only got 1 egg in two separate clutches is yet another indication that something is going on with your breeding-pair health-wise...
***How old are your birds? How long have they been a breeding-pair? What is their regular, daily diet?
The other question to ask is what type of Incubator are you using? Is it a "still-air" incubator, or does it have a circulation fan? That makes a HUGE difference when choosing the incubation temperature, because if your incubator is a "still-air" incubator and doesn't have a fan, then you have to raise the incubation temperature because a "still-air" incubator is only emitting heat at one, single point on the egg, typically the top of the egg where the bulb is; In contrast, an incubator with a circulation fan is going to keep the hot air circulating all around the eggs....So if your incubator doesn't have a fan, you must compensate for the lack of hot air all around the egg by increasing the incubation temperature at that one single point of the egg, usually at the top of the egg, that is being heated...
Also, with humidity, this is a huge factor and also depends on the type of incubator you have, and whether or not you've been watching the air-space in the eggs or using the weight-loss between setting and pipping...
Also, what turning-intervals did you use, specifically in the first 10-days of incubation? And was the egg kept on it's side?
Honestly, since you got the same result with the hen incubating the first egg as you did using an artificial incubator, combined with only getting 1 egg per clutch, I'm going to go ahead and say that the issue probably has much more to do with your birds than with the artificial incubator settings, and I highly suggest that you get your birds to a CAV for complete blood-work and an x-ray of the female to see how her reproductive system is functioning and what her metabolic/nutritional levels are...It's likely that you may have to drastically adjust or change their diets, or at least her diet....It's also extremely likely that your hen has already been bred over and over again, and should not be bred anymore at all because it could extremely dangerous to her health, and could even result in her death. Whenever you buy a "breeding-pair" of parrots from someone else (who presumably told you that they were a "proven pair"), you have to get a full picture of the bird's health, specifically the hen's health, BEFORE you attempt breeding her again, because you never know what you're actually getting.
