Queen Widow spider butt is big enough to hold 4 mares, 2 stallions, and 10 foals. Yes, there is a LOT of room in there to hold 10 foals or more.

She might be able to hold 3 stallions (depending on the size of the stallions) and 5 mares ( depending on the size of the mares)

Widow is the only spider pony that can hold that many ponies in her spider butt~

(Of course, I may "sometime" break this rule when I make vore art of her >>)

Widow can mind control multiple prey at once, however the prey must be making eye contact with her.

(It's possible to break free from her control, but don't expect it to be easy)