I don't think so. Lots of hive types have much smaller entrances than Langstroth (including natural ones - colonies living in trees, as an example). In any case, keeping mice/voles out is a good thing. They don't investigate hives only in the winter.Is it bad to leave the guard on all of the time?
I am considering leaving mine on all year. Would this be a real problem? The metal mouse guard I bought has 17 bee-sized holes at the bottom. I am thinking I won't have to worry about them getting too hot (being metal) because my rain shields extend 6 inches over the front of the hive, so the east-facing entrance would be in shade by noon.
I live in Washington state and I'm currently a little paranoid about the threat of Asian giant hornets (aka "Murder Hornets") that were found in the state last year. I'm concerned they are here to stay - generally when an invasive species is introduced, eradication efforts only slow their spread - and worried that one day I'll open a hive that was fine the week before and have dozens of giant hornets fly out and sting me repeatedly. The holes in the mouse guard would be too small for giant hornets to fit through.
I am thinking I will test on one hive to see if it causes too much congestion. I feel like the only reason I would really need to leave it off is if I'm trying to raise queens and don't want to interfere with mating flights.