Getting the first 3 children(items) for each owner in a list of primary keys
You can use window functions to solve this kind of issues, something like:

select item_name
from (
    select name as item_name
         , row_number() over (partition by owner_id
                              order by id) as rn
    from items_item
    where owner_id in (64, 65, 130, 99, 43, 140, 108, 143, 115, 154)
) as t
where rn &lt;= 3


I updated to order by id in window clause, according to comment