Average litter size for females was 6.22, with less than one puppy on average being stillborn. (ashgi.org)
25 years of neuter / return has effect comparable to reducing average litter size from four kittens to one MOUNT RANIER, Maryland ---- The largest return of data yet from a national survey of cat rescue and sterilization programs shows a cumulative reduction of 72 % in kitten births at monitored colonies since the introduction of neuter / return feral cat -LSB-...] (animals24-7.org)
The average litter size was reduced by 10 % to 20 % at all doses compared with controls, but it was most reduced at low doses. (sciencemag.org)