I didn't see it stated anywhere for this year's contest.  But in 2020, the Ann Whitford Paul winners were announced mid-June.  See here:
https://www.facebook.com/SCBWI/photos/a.129189255298101/174059097477783/?comment_id=174465020770524

FYI, back in early February, I received a rejection letter for the contest. I decided to take my finished ms and try to get it published elsewhere. I'm happy to report that I was successful in doing so. My entry was written as a NF piece, which might have hurt my chances in the contest. Anyway, the ms was published several weeks ago in Paranormal Underground Magazine and I actually got paid for it! So if anyone falls short on getting into the book, try what I did. Good luck .

Ken

Happy sales to you! It's always great when you can repurpose something.

I'm interested as well if it's not too late. Email is JackBakerComedy@gmail.com

I was thinking the same as dkshumaker. 3 pages could easily be just 30 words out of a 400 or so word manuscript. Perhaps because they asked for a proposal, then wanted to check the text to be sure it isn't "too challenging", this is an Educational/early reader book publisher?
In any case, agree that publishers assume the Author will work with the Editor assigned, to make any changes to text and art. You needn't mention your willingness.
 

Hi there, @lerg1!

I agree that joining a writers' group or exchanging manuscripts with others is also a great way to get input on your story, but if indeed you're looking for a paid critique, please give me a shout if I'm in Canada (not the UK) and I offer critiques of children's manuscripts, from picture books and chapter books to MG and YA novels. Please get in touch for more details: susanhughes@sympatico.ca.  And here's my website page where you can find out a little more as well: http://www.susanhughes.ca/manuscript-critiques. 

Susan