“Has everyone forgotten the Braekel chicken issue?”
Who can forget those pashkevilim insisting that all contemporary chickens are treifus, invoking a number of chashuvah rabbonim including R’ Wosner’s Beis Din etc. Some were machmir to the point of not only foregoing chickens or eggs but also anything made with egg derivatives (such as mayonnaise). In reality, I suspect that all commercially available chickens on the market today have been hybridized with unknown types.. Fortunately, virtually all hashgachos relied upon today, including the gold-standard chassideshe hashgachos, have no kashrus concerns with chickens on the market.