I’ve never heard about joint problems due to 20% feed so it may or may not be a thing. Joint problems can occur with high calcium content do to gout from kidney problems, or if there’s another organ health issue going on. For this reason non laying females, males, and juveniles shouldn’t be fed layer feed long term because the added calcium can create problems.
Liver problems can develop from really high protein/ long term obesity.
Another issue is angel wing which has been attributed to too much protein and carbs in their diet while growing. Others argue that it’s genetics and has nothing to do with diet. In my opinion it’s a mixture of both. Differing metabolisms among individuals can process their feed differently, what’s fine for some may not be enough or too much for others.
In a gaggle of 4 goslings I had one start developing, none of the others did, and of all of my 20 geese I’ve had shes been the only one to get it so far, and I feed them 20% Purina flock raiser more or less year round at every age.
Angel wing isn’t really something that can be predicted, if you have a gosling get it but the others seem fine I’d say you probably don’t need to adjust their feed. If you have multiple goslings develop it some adjustment is probably necessary. If angel wing does appear it’s easily fixed by wrapping the wing in the correct position for 3 days “if caught early.” If left alone the twist becomes permanent.
Angel wing itself is actually the twisting of the wrist bones when the first blood feathers are coming in. The weight of the new feathers is sometimes too much for the gosling to hold their wing in a normal position and as the bones are growing they can be warped.
I’ve wondered if not enough protein and calcium can also cause angel wing due to poor weak bone development.
Large breed geese also have higher nutritional needs, so for my Toulouse and for embdens or super Africans 20% is just right, for smaller breeds like Chinese or Romans 20% might be a little too hot. My Roman has never had issues though.
Medium breeds like smaller Toulouse, Buffs and Africans need to be monitored more.
You can also follow Metzer’s guide
https://www.metzerfarms.com/nutritional-requirements.html
Personally I think they must keep their large breeds too slim if they follow their own guide. 14% maintenance feed hasn’t been enough to keep my medium to big boys at a healthy weight but different geese do have different metabolisms.
I have two feeding methods, the monitored method and the hands on method.
monitored method.
20% - 22% feed from 0 to 4 weeks.
18% finisher or 18% mixed with 20% from 4 weeks until fully feathered.
20% feed once freezing weather and laying begins. Added oyster shell free choice.
16% to 17% as a maintenance feed when no one’s laying or molting.
20% feed when molting.
hands off method
20% all year, at every stage. Added oyster shell free choice when laying.
With this method you do need to monitor them for obesity and make sure that they get plenty of foraging time and exercise, especially for medium to smaller breeds. If you can’t feel their keel they’re too fat. For “keel-less” breeds thats a little trickier, so you’ll have to weigh them every few weeks or at least monthly.
30% game bird or meat bird feed for when underweight or severely ill, Do not feed this otherwise.