Lactating mares produce more milk once they begin having the stimulation of a foal drinking. The initial production is limited to make more resources available for the growing babies. Mares that are nursing while pregnant will have smaller litters as a result.
Nursing, nutrition, and stress are the three biggest factors in litter size. The popular mummah surprise line from hasbio feeds the pregnant fluffies a specific diet to produce an average litter of three foals.
Domestic fluffies tend to have larger litters and ferals with special friends or herds to tend them will usually reach 5 to 6 and are also likely to become immobile.
Well they advertise a range of litters so you gotta have a few XXL mummahs and a few mid sized litters for those with genes for alicorns. After all you gotta keep the FTC off your back
Least Problematic: She stillbirths or doesnt produce milk when her babbehs are born due to her body thinking it has done its job (Bad for her, but doween isnt a threat daddeh could protect his babehs is doween decides to do some stompies out of spite)
Most probomatic: shes been in the wild too long and shes riddled with diseases results in very bad miwkies (In which case it could be game over for the babbehs)
doween isnt a threat daddeh could protect his babehs is doween decides to do some stompies out of spite)