I would like to get the title "Room for One" but I have already 10 pets. Can somebody give some advice as how could I temporary transfer my pets to for example another account or something like that?

I believe the rules state that you can only own one account. I know what you mean, I have 13 pets and am about to adopt another soon. I have heard of people and their friends getting together and giving their pets to a friend to get the achievement. Not sure how that fits in with the rules though. XD

Many people won't get this if they are old timers to the site. I'd imagine though if you can bear to part with your pets for a month friends could help, otherwise you could do the pound and have friends adopt then send back thing but the pound is risky...

You can get it if you already have more than one pet, but it is a pain. I had to find friends trustworthy enough to hold onto my pets for 30 days(because of the wait time between transfers) to get the achievement. I've heard of others dumping their pets in the pound and adopting them all back before anyone else got them, but that I would never risk. xD I love my pets too much. lol

Thank you all for helping me with this issue. :) I haven't decided yet, whether I'll go searching for trustworthy people to transfer my pets to or not.