My chihuahua's were locked together yesterday and today, can they conceive both times, and if so would she have pups on different days? It is both there first time. I can't believe how scared and nervous I feel already, as he is bigger than her. She weighs 5 kilogram and he weighs 7 kilograms ( not sure in pounds) I couldn't bare it if anything happened to her.

Hey, don't worry, she will be ok :)! The puppies will be born in the same day, 63-th day from yesterday, more on less with one-two days. Between 9-th and 13-th day of her period she can have the pregnacy. But the puppies will born in the same day. Waiting good news from you! Good luck!   

Thanks so much, It great to have support from people on here who have more experience.

You're welcome! I'm glad if i can help! Anytime you will nedd, please feel free to ask me!