Thank you so much for all your replies. I had trouble logging in and I ended up cleaning up the cage and dumping the hoard
Hammy has been less active after that. Aside from the hoard, I think the problem is that I have used less bedding. I am going to add more now, and place some seeds under it.
She has a sand bath (that I filter periodically) and I have noticed she pees on the wheel and on the top plastic floor (very easy for me to wash clean every week or so). For the mix, I have used Vita Garden and I also bought Vita Seeds (mostly millet) as I thought she liked it a lot (before realizing there was a lot in her hoard). She does not eat the flakes (veggies?) and the cylindrical pellets.
I will keep you posted abot the new developments and thanks again!