You may have a rendering assigned by the default template values, each new item will have a PageTeaser rendering.
If you want to automate this process, look at the <mvc.getXmlBasedLayoutDefinition> pipeline, we will add general visualizations by expanding this pipeline.
Update
I found some code examples and blog entries that should help you in the right direction to manage layout details.
public void AddSublayoutToItem(string itemId, string sublayoutId) { using (new Sitecore.SecurityModel.SecurityDisabler()) { if (Sitecore.Data.ID.IsID(itemId) && Sitecore.Data.ID.IsID(sublayoutId)) {
Taken from here - http://www.bugdebugzone.com/2014/06/how-to-add-sublayout-to-sitecore-item.html
Also several other related blogs
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