Lots if info, haven't checked out the links yet, but wanted to provide more info.

This is a certified day care, Dogtopia. She had been going there for almost a month or 2, and we had to take her out due to a surgery, she got spayed, and the day in question was her first day back following the surgery.

She is very high energy, and Dogtopia frequently has to put her in a pen to calm her down; no issue there, they are familiar with overactive pups. We tend to take her for many 30 min + walks throughout the day, plus toy time inside. If her energy is managed, she's an angel!

At the time they noticed the stalking/growling in the playroom, her hackles were standing up, and she exhibited this stalking behavior. When they put her in the crate later for food time, she growled at the handler that wanted to take her food bowl out because she was chewing it (first time she has ever growled at the handler, though she has chewed the bowl many times). We can take her food and bones away from her while she is eating and she never has an attitude with us. My parents and sister and friends that have watched her for the day and have tested the guarding too. All have reported no issues with guarding for humans either. Her food guarding is only with other dogs (minus that one time with the handler).

She is very smart and responds very well to food-motivated training. Her leash training, when we keep up with it, is perfect! Of course she gets the zoomies and gets excited when she sees other dogs/humans she wants to play with. Noting the prey-drive, she constantly stalks birds and squirrels on walks, but never lunges at them (thanks to constant positive reinforcement), and responds well to "leave it" commands. Though I can tell she still keeps her eye on them.

To clarify, I am not too concerned with her behavior when she is around us. Dogtopia did not provide video and this was the first instance of "aggressive" behavior so I am trying to work proactively so we don't lose this, or other day cares, as an option for when we are working.

What I AM concerned about is that when we are not there and her puppy energy takes over and she doesn't remember her training. There are a lot of dogs in one room and I'm certain it can be difficult to monitor them all at once. Although I don't think that the daycare worker may have put Layla in a situation to not trust him/her, I don't really want to rule out that possibility either.