Help! Not used to being "caged"

[GranvilleGSD]

I am planning on having my first litter soon, and am very concerned about what will happen when Izzy is penned in with the puppies. Izzy was crate trained as a puppy, and is very calm in a crate all day long at dog shows, or in a kennel environment, but during the day at home while I am at work, she always has free range of the house. It has been this way for nearly 2 years. Since she is in heat right now and I now have an intact male pup (6 mos, and seeming very interested in her), I decided it would be best to crate them both at home, but she is throwing a fit! Screaming and barking and bouncing around, somehow she managed to pull a pillow through the bars of the crate today, didn't destroy it or anything, just pulled it in the crate. I am concerned that she will behave this way when confined with the whelping box and x-pens. I have partially set up the area, and been working towards calm, happy associations, giving her some RMBs or stuffed Kongs to work on while penned up while I go off and do things around the house. Do you think the motherly instinct will take over her and she will be calm while penned up, or is this going to be a major problem for us?

[GSDextrodinaire]

First, she is currently in heat so behavior you observe now could be totally different when heat is over, and hormones return to normal. Test her in the crate a few weeks after heat and see the reaction.

Secondly, most females when they have puppies, don't want to leave their puppies, you usually have to drag them away from the pups to go outside. Until the pups are a couple weeks old, a lowered gate for the whelping box does allow for mom to get in and out. My female never bothered with that, and hopped over the sides when she wanted out.