she may be egg bound if she has been laying well the white liquid is urates the urine in chickens . take her into a warm place and look at her vent is it red and protruding? if so put her in a bath of warm soapy water .this will relax her vent hold her there for about 20 mins ,rub some vasaline or ky jelly around and just inside the vent ...... do not put any pressure on the stomach as this may break the egg and cause even more problems, i do this with bad birds and usually get results , next if you get an egg out you need to isolate her on paper and straw she may well have other eggs locked up behind the first with luck she wil pass these . if you dont see an egg you may need to get it out manually . using ky jelly just put a small amount on the tip of one finger and massage it inside the vent . now gently massage the lump down from the rib to the anus ,now if an egg pops out do as above and isolate her . she may well now have a prolapsed cloaca to put this right pop it back in with a finger ... like putting a finger in a glove .turn your finger right to left as you remove it to leave the prolapse behind .. now put the chicken on only wheat and water for a couple months and isolate it for a full week to 10 days until it perks up making sure it has grit and oestra.this will stop other hens attacking her vents also this feeding may bring on a moult and she wil stop laying so giving her innards a chance to repair ......
if in the event an egg breaks inside her remove the remains very gently and wash her vent with warm salty water to prevent bacteria building up
if you see cuts on her cloaca vent treat with hydrogen peroxide.. hope this helps .. also treat her with a bit of dandelion leaf daily