I dealt with this recently.
do not feed the feed to your horses.
The problem is, weevils are attracted to feed, so being the bags sat in your barn for a month and a half, and depending on how anal your feed suppiler is, they may say that the weevils came from YOUR barn.
I always clean up an excess feed dropped and use feed ASAP after purchasing it. the feed I got with weevils in it I had just bought that day, but it had sat at the feed store for abit, so Im thi8nking thats where they came from.
I also will not buy feed that has been sitting at the dealers for awhile, particulary sweet feed(the weevils seem to like it more)
Not a fun thing to deal with.