Mouse Guards

[Millet]

I keep seeing and reading about mouse guards BUT Why, i have a entrance that is around 7mm high and it can be as wide as i want it to be, it is that height in mm for wasp/robber defense and even better at this time of the year for mouse control.
So my thinking is with open mesh floors and 7mm high be entrance blocks they will be more than enough ventilation, so why mouse guards, there's not a mouse in this country that can squeeze through a 7mmx 100mm x 100mm space, unless it has octopus DNA in its make up.

 

[Erichalfbee]

Yes, a slotted entrance like you describe has no need for a mouse guard.

 

[user 6228]

why fit an external mouse guard when you can have 10,000 internally?

 

[iand]

I agree it is the entrance height that matters.
Not used mouse guards for years.

 

[Millet]

why fit an external mouse guard when you can have 10,000 internally?

Its no good though if 10.000 little ******* are napping above.