They are looking at eggs as a way of manufacturing antibodies. So what they are saying is that the antibodies that they developed in egg yolks were effective.Well, if they inoculated the egg yolk with covid and it neutralized the covid pathogen wouldn’t it do the same thing in a human like the article says? Not sure I get what your trying to say here.
The other antibody treatments were developed in mammals. But eggs are a more efficient way of making the antibodies which is why they are looking at it.
So nobody would care about all our backyard eggs - or indeed any egg that had not been through their process to cause it to manufacture antibodies.