yes stupid question,
missing toe nails can be mechanical damage, ie: caught in something
symptom of calcium defiiency, ie weakened claws snap off
fungal infection, ie under nails and they drop off
may also be symptomatic of other things
this is just my experiences
didn't want to be an alarmist
all things must be considered with general appearance and demeanour of the animal and its environment
blood tests can determine many things but then you need a vet experienced with reps to determine what the results indicate