Mind you this is all just my opinion and this is what I think...
I would not suggest dog food at all for a staple for rat feed.
Least of all dog food from walmart. Yes it may be cheap but cheaper most of the time isnt better.
Why cut corners with your feeders food for investment quality snakes? I look at it as whatever im putting in my rats stomachs are going into my investment BPs so why wouldnt i feed them the best? If I spent thousands on snakes, I will go the extra bit to make sure they are fed right.
Most dry kibble isnt even good for a dog to live on for its whole life.
Im just saying as a staple diet I would go with a rodent pellet such as mazuri. They come in all size bags and it isnt all that expensive. In addition to the pellets I then feed mostly grains, which include bagels, whole wheat breads, granola bars, oatmeal, cereal, cooked rice, etc. Then veggies, collard greens, broccoli, etc. They can have most anything for table scraps.
Im not trying to judge or seem like im rude in this post, its just that a lot of people are under the misconception that dry dog food is great for rats. I personally dont agree.
If you want to use dry dog food as a staple just please give them additional grains and fresh veggies. And keep in mind that just because their feeders doesnt mean they dont deserve a great diet so that your snake can benefit the most from them.
Again this is all IMO!
I hope this helped you.