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I use to raise jack russell terrier and you can start to give them solid puppy food at 3-4 weeks of age. Pour hot water over dry food and let set until soft.you may have to put some food in their mouths to get them started eating. You can wean puppies at 8 weeks old.
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You can aspiration liquids and food my in-law had to thicken liquid to be able to drink it. And their solid food had to be a certain  thickness to be able to eat it. The best thing to do is look it up on line. Just ask the same question in a search engine.
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They will come into heat around 6 -8 months of age. They are still puppy at this age and have not threw growing. You should wait for the second heat. She will come into her second heat 6 month after her first heat cycle.