im really worrid now.

about 2 weeks ago one of my female macley stick insects passed away for no apparent reason, and now it seems like my other female is going down hill !

she is sitting at the bottom of her plants looking very lethargic, she also has a dark brown sercretion coming from her bum which is also worrying me

does anyone have any idea of what i may be doing wrong ?
can they get diseases ?

please help me

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animals are my life

i have:
2x dogs (rottweiler and a jug),
1x african grey parrot,
2x rosella parekeets
4x syrian hamsters (baby, mocha (wiggy), peaches and daisey),
2x winter white dwarfs (sunshine and harry),
1x female leaf insects (doesn't have a names),
1x female corn snake (awaiting eggs),