I have three young dogs, a 9 week old Rottweiler, a 5 month old Italian Greyhound and 1 year old pug. I have not used crates in the past, can I start using them now and if I do crate them would I have them separate or together. The IG and Pug are always together so would this cause separation problems if the are not together. The crating not be very often just the short times when nobody is home.