This would either be because it is a bundled item (Hydra does not list Walmart Bundled Items) or the item is being sold by a 3rd Party Marketplace Seller and not Walmart.  Hydra now has ability to list 3rd party marketplace sellers.  All you have to do is add #skuopt:all to the end of the supplier url.


Let's look at this example:

http://www.walmart.com/ip/Allen-Sports-Deluxe-3-Bike-Trunk-Rack/23091634


This item is being sold by BikeWagon on Walmart's platform but not sold by Walmart.




You see under Add to Registry/Add to List, Walmart shows the item is being sold by Bikewagon and not Walmart.


If you try to list the regular Url with Hydra, you will receive the following error: There was a problem retrieving a product from the supplied url



To solve this problem, add #skuopt:all to the end of the supplier URL. So the original url would go from


http://www.walmart.com/ip/Allen-Sports-Deluxe-3-Bike-Trunk-Rack/23091634 to 
http://www.walmart.com/ip/Allen-Sports-Deluxe-3-Bike-Trunk-Rack/23091634#skuopt:all

If you use #skuopt:all at the end of the url, the product information will be pulled and you will be able to list it.  Also, if you are tracking & repricing with skugrid, when the item exports to skugrid, it will be set to track with the option All Vendors set...and will remain in stock until there are no vendors on that particular item. On the other side, if you only want to use Walmart fulfilled items then add #skuopt:walmart at the end of the url instead.  That will exclude 3rd party sellers.