Filling holes in chipboard flooring

[Pollyanna]

All my floors are bare at the moment after a flood caused a lot of damage about 7 months ago. The house has been empty, with exposed rafters and I have found signs that there have been mice about (mouse droppings in my bed would you believe!). Some damaged boards were replaced and next step is getting the carpets down BUT, I am a bit concerned about the number of holes that there are which are of ample size for mice and probably big spiders to get through! These mostly occur around the edges of rooms, for example behind the radiator pipes and between old boards under the stud walls (which obviously could not be lifted) and the new boards. I'd like to try and get those filled before the carpets come. Any suggestions as to what to use and how I might go about this please?

[Discoeye]

https://www.screwfix.com/p/ronseal-high-performance-wood-filler-natural-550g/51811     Two pack wood filler would be fine for the job, don't sand it just fill flush or wood glue and sawdust.