My husband and I have two laying hens (they are a mix of Bard Rock and Rhode Island Red). We keep their feed in a plastic airtight container/canister. It is outside but in the shade. We access it once a week to refill their auto-feeder. After a month or two, the feed is getting moldy in the container. It could be from heat and humidity, but everything I've read says to use an airtight container vs a vented container. Which is better? Any other suggestions? At this point, we are going to next try storing it in the garage but still in the airtight container. Thanks!