AWWW - they are all so gorgeous!
Hoster doesn't look especially pregnant to me, but keep her weight monitored.
If she were pregnant, at that stage she should be very thirsty. the belly would bow out just before the hind legs in the later stages; you would also feel any hard balls, I you gently feel her belly when she sits on your hand.
Some girls are just chunky - look at my Nerys, guaranteed NOT pregnant, though she has given me the odd moment of panic!