Alright, first of all STOP PUTTING VITAMINS OR ANYTHING ELSE IN THEIR WATER!!! They don't need any type of Vitamin supplements unless they have blood-work done and they are diagnosed with a deficiency of some kind, otherwise giving them a Vitamin supplement of any kind can actually do way more harm than good, and all they are going to do is pass the excess Vitamins you're giving them out of their bodies in their Urates (the water-soluble vitamins in the supplement) and the fat-soluble vitamins will only accumulate in their fat-cells because they can't use them, and then they develop Vitamin-Toxicity and Poisoning...And you cannot and should not EVER put ANYTHING at all in their drinking water, not any medications, not Vitamins or any other supplements, etc., because it immediately contaminates their water and bacteria and fungi/yeast starts growing immediately, and usually they just end-up developing multiple Bacterial infections throughout their Gastrointestinal Tracts...So STOP giving them any kind of Vitamins. They don't need them and you're only going to end up with sick birds that will need Avian Vet care, and because they are wild-caught CAG's no Avian Vet will see them. All you need to provide them with is a large Avian Mineral-Block and a Cuttlebone so that they are getting ample Calcium, Phosphorous, and Vitamin D. That's it, no "multi-Vitamin" supplements at all, and NEVER anything in their drkinking water!!!
Now that we have that out of the way....Have you ever actually bred parrots before? Or a better question is have you ever actually pulled just-hatched babies that are between 2-3 weeks old from the nest-box and hand-raised/hand-fed them before? Because if not, these two wild CAG's are not the place to start, that's for sure...Chances are that even if you do get them to breed by some miracle they are going to be horrible parents, and you'll be forced to remove any babies from them, have to house them in a proper Brooder (do you have a Brooder?), and have to hand-raise them on your own from very young. And if you have no experience in doing that, and if you don't have the proper equipment to do so like a Brooder to house them in (they'll die of fungal/yeast infections if not kept at the proper ambient-temperature range according to their feather-development/growth), a proper digital cooking/candy thermometer with a metal-probe to ensure that the hand-feeding formula is ALWAYS between 104 and 110 degrees F at all times while they are being fed (again, they'll die of fungal/yeast infection if their formula is even a degree or two cooler than 104 degrees F, and if any hotter than 110 degrees F you'll burn their crops)...It's just not something to start doing with a pair of wild-caught Greys that have a propensity for fighting if conditions are not just so...
And on that subject, it doesn't matter where you got them, whether they were a "breeder" or not, I would be willing to be everything I own that this pair of Greys have NEVER had a successful clutch of babies, they probably haven't even ever bred before based on the behaviors you're describing. This is nothing new, breeders buy a young pair of wild-caught parrots in hopes of them breeding, they keep them until their optimal-age to start breeding (WHICH FOR CAG'S IS ABOUT 7-8 YEARS OLD BY THE WAY), and if by then they don't show ANY SIGN of being a successful breeding-pair of birds, they dump them, selling them to someone as a "Proven-Pair" of parrots who have successfully bred and raised babies before when in-fact they haven't even ever started to breed...7-8 years-old is the optimal age to START breeding a pair of African-Greys, so if this breeder told you that they've already bred and raised a single clutch of babies, they most-likely lied to you, and they dumped them on you because they are well aware that they are not going to be a successful breeding pair of Greys...Sorry, but I'd rather tell you the truth than lie to you like this breeder did. We've seen this time after time after time, and the bottom-line is that there is absolutely no way to force them to breed, and if they have already shown a propensity to physically-fight with each other, then they are not going to be a successful breeding-pair of birds...It's just the truth.
In-regards to those cages you have inside of your home, they aren't large enough to keep little Budgies in, and if you even attempt to keep them inside of those cages they are never going to breed successfully; even a proven-pair of birds who have already bred and raised multiple clutches of babies won't EVER start to breed if their environment is not at least "adequate", and usually it needs to be "optimal" for a wild-caught pair of parrots to breed in-captivity,, so you've got multiple issues going on here...And if they are a wild-caught pair of African Greys, they are certainly not going to be happy living inside of your home, they would be happiest inside of a large, outdoor Aviary LIVING TOGETHER! So if this pair of wild-caught Greys were physically-fighting while LIVING TOGETHER inside of a large, outdoor Aviary, what does that tell you? They certainly cannot live TOGETHER inside one of those cages you have inside your house, and if you don't house a "breeding-pair" of parrots together, they aren't going to remain bonded (if they're bonded in the first place), and they certainly aren't going to breed...And again, if they were fighting while living together inside of a large cage/Aviary outside, where they should feel most-comfortable, then they aren't a breeding-pair, nor are they going to become one...
As far as their diet goes, they need to be eating a daily "staple" food, which needs to be either an Avian Pellet, which is best, especially for a breeding female, or a seed-mix, but it must be a low-fat, high-protein seed-mix that contains NO SUNFLOWER SEEDS AT ALL, NO NUTS AT ALL, AND NO DRIED CORN AT ALL!!! Those 3 ingredients are nothing but fat, and will result in enlarged-Livers in both birds, and an enlarged, fatty-liver in a female will prevent successful laying of fertile eggs. And giving them an artificial Vitamin Supplement is not going to do a thing to help the problem, as most of the water-soluble vitamins in the supplement will just pass out of their bodies without ever being absorbed, and the fat-soluble vitamins in the mix will just be stored in their fat-cells, including the ones in their livers, and eventually cause vitamin-toxicity diseases. They must get their daily-nutrition, including their protein, vitamins, minerals, amino-acids, etc. FROM THE FOOD THAT THEY EAT, NOT FROM A SUPPLEMENT. So if the seed-mix that you're feeding them as their staple-diet each day contains ANY Sunflower-Seeds, Nuts, or Dried Corn, then you need to find a new parrot seed-mix that doesn't contain any of these things, or you need to transition them over from the seed-mix to a daily-staple food of an Avian Pellet. And either way you need to give them a large portion of fresh Veggies and Dark, Leafy Greens (NO WATERY LETTUCES AT ALL, THEY CONTAIN NOTHING BUT WATER), including Mustard Greens, Collard Greens, Turnip Greens, Dandelion Greens, Arugula/Rocket, Watercress, Bok Choy, Chard, etc. And fresh Fruit should only be an occasional treat and IS NOT interchangeable with the fresh Veggies and Dark, Leafy Greens, because ALL FRUIT is full of natural SUGAR which is just turned into FAT and stored in their livers just like the fat from the Sunflower Seeds, Nuts, and Dried Corn is...The only one of the bunch they should get at all are the Nuts, BUT ONLY AS OCCASIONAL TREATS AND NOT AS THEIR ACTUAL FOOD!!! And NO PEANUTS!!! They contain little nutrition and are extremely high in fat, and also carry deadly molds and fungi...Almonds, Filberts/Hazelnuts, Brazil Nuts, Walnuts, etc. Just no Peanuts at all, and all Nuts are just occasional treats just like the fresh Fruit is...And STOP THE VITAMIN SUPPLEMENT UNLESS YOU GET BLOOD-WORK DONE AND ONE OF THEM IS SUFFERING FROM A SPECIFIC VITAMIN DEFICIENCY, in which case you only give them the Vitamin that they are lacking, and you give it to them by either an injection or on their food, NEVER IN THEIR WATER!!!
I think you've got a pair of wild-caught CAG's that is not a breeding-pair, has never been a breeding-pair, and their "breeder' most-likely lied to you about them having produced a clutch of babies before...They can show you all the photos in the world of baby Greys, but this pair of Greys does not at all sound like any successful breeding-pair of birds I've ever seen. Like I said above, a wild-caught, non-tame breeding-pair of Greys should be happiest living OUTDOORS, and living TOGETHER in a large Aviary that is outdoors. That's the most-successful set-up for breeding a wild-caught, non-tame pair of CAG's, is them being housed together outside in a very large Aviary...But this pair was fighting so much when housed together outside in a large Aviary that you actually had to move them indoors and keep them living separately. That should tell you all you need to know about whether or not they are a successful or even a bonded pair of Greys...
I'm sorry that this happened to you, it's terrible for "breeders" to do this to unsuspecting people, because now you've got two wild-caught, non-tame Congo African Greys who fight whenever they are put together inside of the same cage outside, which is where they should be most-happy and content, and where most successful, wild-caught breeding-pairs flourish and breed healthy clutches of babies, especially a breeding-pair of CAG's that are around 7-8 years-old, that's the perfect and most-optimal time for them to start breeding successfully in that outdoor environment.