I leave mine out from may until end of December or even January.
Deer in Alberta should be fully grown by 2nd to 3rd week of August and start rubbing their velvet off in the first week of September
3 of mine I have in the field all year. From those im looking for post hunting season info,When they drop antlers. I have all mine out between April-December.
Right now is actually great to see how the animals have grown and start finding out what animals have returned for another year.
Last year I personally found antlers were late in maturing and velvet came off much later then im used to seeing it. From what I have seen this year I expect it to leave early