Well, according to the descriptions and pictures I've seen, they are all supposed to have dark feet so I guess that the mottled ones that Sunny has are just an individual pigmentation issue. Now, if they both have yellow on the head, they would have to be meyeri, saturatus, matschiei or trasvaalensis but the last one has very little to no yellow so if they both have significant yellow, we can exclude this one. Of the ones that do have yellow, meyeri has a turquoise belly, saturatus a geen belly and matschiei a blue one so looking at their bellies should be the way to determine which subspecies they are. The problem with pet birds is that breeders are not really very picky or even knowledgeable about subspecies so they breed a male to a female, even if they are of different subspecies, and we ended up with a lot of crosses that can no longer be identified as one subspecies or another.
Overall size and beak size can be individual or even blood lines traits... My CAG is what used to be called a 'Cameroon' Congo. Importers and breeders claimed it was subspecies of Gray because they were larger and a lighter, more silvery gray than the norm but it was nothing than a marketing trick (they were more expensive) -same as the famous Longfeathers of the peach face lovebirds.




