Sorry, but your roosters are hardly silver but silver plated.
Of pure curiosity I took the risk and open the links because i have similar objects. What I believe has happened is that an acid test has been made. It showed very high silver fineness. The reason is that an electronically plated object's silver surface is always 100% silver. The problem with this test on a silver plated object is that the needed scratch hasn't been deep enough and has therefore not reached the base metal. It is usually German silver, alpaca, brass... In addition such objects are seldom made of silver. The marks are fantasy marks.