<?php
function display_facebook_pixel() {
	if( is_page() ) {
		// your tracking code for default pages, although you may need to be more specific about which pages.
	} elseif( is_shop) ) {
		// your tracking code for the main shop page
	} elseif( is_cart() ) {
		// your tracking code for the cart page
	} elseif( is_product() ) {
		// your tracking code for a single product page
	}
}

add_action('wp_head', 'display_facebook_pixel');
?>