My mare Kelly Do is in foal with Backseat Driver, the foal due on 7/2/07. So it says everywhere else but on the “Breed This Mare” page, where the date changes every time you click it. The scariest one I saw was “Kelly Do is in foal to Backseat Driver, and is due to foal around July 29th, 2011”. Why does it change? It said the real date only once… why is there such a big range?
I didn’t think it was a bug (maybe it is?), but I’m just curious. 
It was a bug, it’s now fixed. 
(When it can’t find the due date in the database, it makes one up based on the baby’s actual date of birth, but there’s error built-in because vets aren’t omnipresent.)
Oh, cool. Glad I spotted a bug to squash. 
Thanks, and you’re amazing.
Shanthi,
I’m sorry to bother you about this.
I remember seeing a post (or a FAQ) giving a range of days that broodmares usually are in foal for but cannot remember where I’d seen it. I vaguely remember something about 335-345 days.
Could you please confirm/correct this information for me.
Thanks.
It is 335-345 days, but mares can have premature babies (up to 3 weeks early, I believe), or late babies (up to 4 weeks late). Also, colts tend to “bake” longer than fillies.
Ah, that would explain why my two mares gave birth a week or so early a few days ago to two fillies. It was the fillies’ fault. 
When a mare is bred and it says that the due date is x, how accurate is that? I just bred three mares today, and, while two of them came up with due dates of Jan 9th, 2013, the third one (the only maiden) came up with a date of Dec 31st, 2012.
Due dates are just a rule of thumb. Mares can foal several weeks premature or several weeks late. As in real life, you will never know the exact due date for sure. So, just cross your fingers and hope your mare foals late.
Good luck!
I had the same thing happen with my mare the other day- bred on the 23rd of Feb and it says her due date is January 1! I wanted an early baby, but that’s a little too early for my taste- I’ll be crossing my fingers and hoping she holds on!