Praise be to Allah.
Collecting stuffed birds and animals, whether they are creatures which it is haraam to collect when alive or it is halaal to collect when alive, is a waste of money and an extravagance in which the cost of stuffing them is squandered. Allaah forbade wasteful extravagance and the Prophet (peace and blessings of Allaah be upon him) forbade wasting money. And this is also a means of making images of animate beings, and hanging them up or setting them up is haraam. It is not permissible to sell them or collect them. The muhtasib has to explain to people that this is not allowed, and he should try to prevent their sale in the markets.