Lol, I know about these big poos.
However, you might want to try Gripe Water (we use Woodward's). We used to have that as babies and now we give it to our babies. It's something our veteran breastfeeding grandma's say we should give to baby generally after every feed but I tend to give it about 2-3 times a day.
Every time DS goes a day without a poo I will give him extra, put him in his little chair (he will be four months in a week's time) and he will definately poo. It also helps with Gripe, wind and digestion.
It's quite good really. If anything it will at least help your daughter to be more comfortable before the big motion arrives.
Actually our elders would be really horrified if a baby went more than 2/3 days without a poo, they would say "definately constipation" and instruct me to take more fennel seeds and Ajwain seeds (you just boil the two types together for 15 mins in water, strain, then drink) but I know the modern thinking is that it is normal and anyway, every baby is different, one may go more one may go less!
Are you giving your daughter Gripe Water?
Hope this helps.