Is it permissible to take money from female students in exchange for their entry to view and sell birds and animals, with them having the choice to buy or not, knowing that some of them are young and lack discernment?

It is permissible for a young girl to buy and sell birds if their price is insignificant or with the permission of her guardian. It is also permissible to pay fees to enter a hall for selling birds and animals if it is for the purpose of viewing, observing, and enjoyment. However, if the payment is solely for the purpose of buying, and does not include viewing and enjoyment, then it is not permissible.