Yes, that could be possible but be a little bit complicated.
As an example:
When you want that all the adoptables get such a code, you need first change your mysql-database. Search with phpMyAdmin (You can find it over the CP of your serverhost) for the _owned_adoptables table and change the table column 'aid' to no AUTO_INCREMENT. Now we need to set the id manually when a new pet gets adopted.
Now we need to edit every file which gives new pets to the users (breeding.php/ doadopts.php). Before the script insert the new pet in the database we need to give it a unique id:
PHP Code:
$timestamp = time();
$id = md5($timestamp);
//first we select the current servertime (time()) than we encode it with md5
//I haven't test this script, it's only an example
$mysidia->db->insert("owned_adoptables", array("aid" => $id, "type" => $row->type, "name" => $name, "owner" => $mysidia->user->username, "currentlevel" => 0, "totalclicks" => 0, "code" => $code,
"imageurl" => NULL, "usealternates" => $alts, "tradestatus" => 'fortrade', "isfrozen" => 'no', "gender" => $genders[$rand], "lastbred" => 0));
(Sorry for my bad english. Hope it's understandable)