I have a nine week old chihuahua girl. We Just got her on Sturday, so still settling in to routines - so far really lovely. Last night she cried in her box (using a large box as a crate as we're house sitting til fri and crate is at home) for the first time. I took her out for another wee at midnight. She cried for twenty minutes before settling. She cried again at two and I took her out for another wee before popping her back, and it took a while for her to settle, but she did until 6 this morning, when she whined a bit and I took her out and she peed and pooed. She has a warm hot water bottle plus rugs and blankeys and fresh water in her box, and is next to our bed.
Obviously she's too small to have in bed, so I guess I'm looking for reassurance that letting her cry it out is the right thing to do, providing she's had all she needs...